Monthly summary & stats 2006

Note: Values in (.) refer to the 10-y 1996-2005 average; [.] refer to the 30-y 1971-2000 climatological average while {.} refer to the station LTA (long-term average) from 1979. All data are subject to verification and amendment. Javascript must be enabled to see the pop-up graphics.

January 2006

A dry and sunny month with temperatures below the decadal but a little above the climatological average.

A changeable month, the beginning mostly wet and sometimes cold, the middle windy and the end dry and colder again.

Overall a dry month the 74.6 mm (78%) of average with a similar [76%] based on the 1971-2000 average. It was the driest since 2001 that had 44.0 mm and ranked 22nd lowest in records back to 1928. There were 17 (+7) dry days this the highest number since 1997 with 17 and ranking 3rd since 1979. There were 12 (-6) rain days 0.2 mm, or more) and 9 (-5) wet days (1.0 mm, or more). But there were 8 days with 5 mm, or more, and this number was +2.3 of average a continuation of the trend seemingly, even in a dry month, of larger rainfalls. The number of falls of 10 mm, or more, were 2 and but this number was below the January average of 2.7 days. The wettest day was on the 10th with 18.6 mm, but the 9th also had 13.0 mm. At the beginning of the month the soil was close to saturation and there was standing water on the 10th and 14th. Subsequently although rainfall was less soil moisture on the 28th was 65% (dry mass), just 5% below the saturated water percentage for the soil at the weather station. There was little evaporation from the lysimeter which recorded a negative value for the month. This was the result of dew and frost deposition, for example, there were independent measurements of net depositions of 0.4 mm on the 8th, 0.5 mm on the 9th and 0.3 mm on the 30th. The Piche evaporimeter housed in the Stevenson screen recorded 24.8 ml of evaporation and was larger because of different temperature and wind movement 4 ft above the ground.

Temperatures were a bit lower than the average of the past 10-y but when compared with the 1971-2000 average a little above. The mean 5.1C lowest since 2003 was (-0.5) and [+0.2] almost the same anomalies applied to the mean maximum 7.5C, also lowest since 2003, and mean minimum 2.6C lowest since 2001. The lowest minimum was -2.2C (+0.5) on the 8th that also saw a low maximum of 3.5C. The highest minimum was on the 19th having 9.4C, highest since 1998, and the mean 9.9C was the highest of the month. The highest maximum 10.8C occurred on the 13th and was 1 of the 5 days in the month to have 10C, or more. There were 6 days of air frost (+0.8) in contrast to last January (2005) that had none. Ground frost numbered 18 (+4.6) the highest since 2001 with 20 days.

Sunshine recorded at RAF Valley amounted to 77.3h, highest since 2003, and was 127% of the decadal average and 141% of the 1971-2000 average. The last decade includes the highest January sunshine record of 93.6 h recorded on a Campbell-Stokes in 2001 (equivalent to 87.3 h on a Kipp & Zonen electronic instrument). But there were 7 sunless days and another 8 days with < 1 h sunshine, the other days made up for this with 7.8 h recorded on the 28th and 29th, the highest in the month. The month ranked the 9th sunniest since before 1930 on the Anglesey record.

There was a windy spell between 10 - 20th having 5 days with gales. The monthly mean wind speed at RAF Valley was 13.8 mph with the highest 33.4 mph on the 13th. Gusts of 53 mph were recorded on the 13th and 20th. Ice precipitation was notable for it's absence; there was no snow and the only day with hail was on the 20th with a few ice pellets. No thunder was heard.

February 2006

Below average rainfall and temperatures but sunshine was above average.

After a dull, cold and dry beginning the middle turned milder and wet. The end, except for one wet day, was drier and brighter.

With 80.5 mm rainfall the month was only 77% of the decadal average. But, compared with the climatological average (1971-2000) it was 107%. The last 10-years have seen February rainfall of > 100 mm in 1997, and 2000 to 2002, and 2004 and makes it an average hard to beat. The long-term average is 76.2 mm and is close to the 30-year. There were 8 (+2.0) dry days and 13 (-6.0) rain days. Wet days numbered 9 (-5.2) while there were 5 (-2.3) days with 5 mm, or more. The mostly dry month was kept moist by 3 days that had more than 10 mm. These were the 11th with 13.8 mm, the 14th with 18.0 mm and wettest the 23rd with 20.5 mm over 18.2 h. Rainfall was more than adequate to maintain the water content of the soil close to the saturated-water percentage of the local soil (which is 70% dry mass). Evaporation recorded by the lysimeter (PE) was 10.1 mm giving a water balance of 70.4 mm; the Piche evaporimeter recorded 25.9 ml evaporation.

The mean temperature 5.0C (-0.3), was the same as in 2005, making it lowest since 2004. The highest mean was 9.0C on the 13th and the lowest 2.6C on the 1st. The mean maximum 7.3C (-1.2) was lowest since 1996 with 6.7C. The highest maximum was 10.6C (-1.8) on the 14th, the only other double figure was the 10.0C on the previous day. The mean minimum 2.7C (-0.3) was highest since 2004 (3.2C). The lowest minimum was -1.6C (-0.5) on the 10th while the highest 8.0C (-0.1) was on the 13th. The mean earth temperature at 30 cm was 5.2C (-0.6) with 21 days below the the 5.6C (42F) plant growth threshold.

Total sunshine recorded at RAF Valley was 84.3 h (106%) and [112%] of average. The sunniest day was on the 19th with 8.6h and was followed by 7.3h on the 20th and 5.4h on the 21st, the brightest 3 days of the month. The 17th had 7.1h and the 14th 6.2h. The beginning of the month was very dull with the first 7 days sunless. Despite this the month ranked 24th sunniest since before 1930 on the Anglesey record.

The month was less windy than average with 1 gale on the 14th with the highest gust of 57 mph. The mean wind speed recorded at RAF Valley was 14.2 mph (79%) and [90%] of average.

There were 4 days with hail, 3 days (15,20 & 21) with ice pellets while the 26th and 28th had snow pellets. The 26th had a little sleet and the 28th, in a precursor to the great March snow event, heavy snow showers early in the day.

Winter 2005-06

The winter months (December to January) had 226.6 mm rain lowest since 1997 that had 218.7 mm. It ranked the 14th driest in records back to 1929 in Llansadwrn, but nothing like as dry as parts of south-east England where reserves are well below normal capacity. In the SE the shortage of water could worsen even with normal spring and summer rainfall as demand grows. Water in the soils here has been maintained close to the water-saturation percentage. Even light rainfall has wetted the surface and produced puddles and pools on surrounding fields. The lowest winter rainfall was in 1964 with 90.5 mm whereas the highest was in 1995 having 510.3 mm. The infamous 1976 had 220.5 mm and 1949 had 253.1 mm.

Temperatures were a little below the decadal average. The mean 5.4C (-0.2) was lowest since 2001 and ranked 14th since 1979. The maximum 7.7C (-0.4) also lowest since 2001 and ranked 12th while the minimum was spot on the decadal average 3.1C. Compared with the 30-year average (1971-2000) the mean 5.4C was +0.2, the mean maximum 7.7C was -0.2 and the mean minimum 3.1C was +0.6. So while the winter temperatures have been closer to the recent past, they nevertheless continued the current warming trend.

The graph shows the mean temperatures and smoothed plot over the 27-years of station records. Fitted to a linear regression the temperature significantly increases over the period by 1C an indication the warming trend that has taken place in recent years.

The histogram shows the mean anomaly (differences from the 1980 -2006 mean) over the same period. Since 1989 there have been 7 winters with an anomaly of +0.5C, or more, but 2006 was only just above the mean.

March 2006

Cold, wet and dull

The first 6 days were cold with lying snow followed by rain. The rest of the month had some sunny days and more rain with temperatures struggling back to normal

Snow fell on the first 4 days and was lying for 6 with 11 cm at 09 GMT on the 3rd and 10 cm on the 4th. It was the most days of snow in March here on this side of the island since 1979 and before that 1965. The first 5 days had snow pellets every day and thunder was heard on the 1st and 4th. RAF Valley recorded only 2 days with snow falling, the 4th and 16th, and no lying snow with largest snow depth "a trace".

On the 3rd the grass minimum fell to -12.4C, this was the lowest recorded in any month since records began in 1985.

By mid-month the mean temperature 4.5C was (-2.8) and [-2.2] of average. The mean was the lowest since before 1979. But 1995 had 4.8C and last year (2005) had 4.9C. The highest was 7.9C in 1991. Mean soil temperature at 30 cm depth was 4.8C (-2.5). Precipitation, rainfall, snow and hail, was 57.7 mm already (93%) and [68%] of average, but the year was running only 2 mm above 1945's total, the driest year since before 1928. But the soil was near water-saturation percentage and the water balance was well in excess with 204 mm.

By the end of the month temperatures had risen to near the average, but the mean finished on 5.3C (-2.0) and [-1.4] lowest since 1979 (4.9C). The mean maximum of 8.2C showed the greatest anomaly (-2.4) and [-2.0], and was the lowest since before 1979, when records began at the station. The highest maximum 12.7C (-4.5) was on the 26th and the lowest 2.3C (-3.9) on the 2nd. There were 8 days that had 10C, or more. The mean minimum 2.5C was (-1.6) and [-0.8] and was lowest since 2001 (2.4C). The highest minimum was 9.3C on the 27th while the lowest was -5.0C (-3.5) on the 3rd. The night 2/3rd also had the lowest grass minimum over snow of -12.4C (-6.9) and was the lowest recorded at this station. Mean soil temperature at 30 cm was 5.7C (-1.6) and lowest since before 1990. Close years were 1995 with 5.8C and 1996 with 5.9C. There were 12 days on which the soil temperature was below the plant growing temperature of 5.6C (42F).

Rainfall was well above average with the 139.9 mm 225% of the decadal average, but 165% of the 1871-2000 average, and ranking 6th wettest on record. The long-term average for March, since 1928, is 70 4 mm, putting the March total at 199%. Eight Marches in the last 10-years have been below average; 1998 and 1999 were above average. March 2006 joins 1998, and only 12 other years, 14 in all that received 100 mm, or more. The wettest March was in 1981 having 205.9 mm while the driest was in 1990 with 18.3 mm. Despite the run of 6 below average rainfalls (2000-2005) there have in the past 26-years been 7 Marches with an anomaly >50 mm, whereas there were only 2 in the previous 52. Heavier more frequent rainfalls have been attributed to an effect of global warming (climate change). The wettest day this month in March was on the 27th that had 19.1 mm. There were 23 (+8.2) rain days, 20 (+10.4) wet days and 11 (+7.2) days had 5 mm, or more. But there were 3 (-7.7) dry days and another 3 saw a trace. At the end of the month rainfall accumulated in the year reached 295 mm above the LTA of 252 mm, but well below the wettest 343 mm in 2000.

Sunshine duration at RAF Valley was 93.2h (78%) and [88%] of average using Kipp & Zonen equivalent values. It was 2.5h less than in 2005 and ranked 15th lowest on the Anglesey record since 1931. Sunniest day was on the 19th with 10.9h and the only other day to have double figures was the 22nd with 10.1h. There were 5 sunless days but another 3 recorded only 0.1h and a further 5 had 0.5h, or less. In Llansadwrn there were 12 sunless days.

April 2006

Very sunny, above average rainfall while temperatures struggled to reach average

A cold and wet beginning, drier and warmer after mid-month, but turned colder again at the end.

It was a sunny month with 190.7 h (134%) [122%] of sunshine recorded at RAF Valley. It was the sunniest April since 1974 (219.7 h) and was the 8th highest recorded on Anglesey since before 1930. Nine days had 10 h, or more and the sunniest day was on the 23rd had 12.4h. There were only 2 sunless days on the 2nd and 30th.

The beginning of the month saw the coldest weather with snow falling on the 8th and 9th and hail on the 3 days 6 - 8th. Thunder was heard on the 8th. There were 2 days (4, 10) with air frost (+1.5) the lowest was -0.6C (-0.8) on the 10th. There were 8 days (+2.0) with ground frost all in the first 12 days; the lowest was -4.0C seen on the 5th and 10th. As a result average temperatures struggled to reach the average by the end of the month. At mid-month the mean was 7.4C (-1.5) and it was similar in the soil at 30 cm deep where the mean 8.4C was -1.6 of average. The mean at the end of the month was 8.8C (-0.1) and [+0.2] of the decadal and 30-yr (1971-2000) averages and was lowest since 2001. The highest mean was 12.9C on the 25th and the lowest 3.7C on the 4th. The mean maximum was 12.6C (+0.1) and [-0.2] was higher than 2005 (12.3C) and equal to 2004; the highest 16.2C was on the 25th (-2.1) and the lowest 6.4C (-1.2) on the 4th. The mean minimum was 5.0C (-0.4) and [+0.6] and was lowest since 2001 (4.4C). Average comparisons show that although the month's temperatures were lower than the last 10-years average it was warmer than the 30-year average indicative of the warming trend. Soil temperatures showed a marked increase from the 15th of the month. At the end the temperature at 30 cm depth was 13.0C, this some 2C above the end of month average. But the air temperature had fallen to 7.8C and was 2C below the end of month average.

Rainfall was 83.4 mm (110%) and [144%] of average. At mid-month 47.6 mm had fallen this (63%) and [82%] of the end of month average. Although generally drier the second half saw the wettest day on the 17th having 15.5 mm. Other wet days were the 6th with 13.0 mm and 9th with 13.5 mm. The month had 11 (+2.4) dry days and 16 (-1.5) rain days. There were 12 wet days (-2.1) and 7 (+1.5) had 5 mm, or more, continued an enhanced heavier fall frequency.

May 2006

Rainfall well above average (ranking 4th wettest), near average temperatures with sunshine below average

The first part was dry with temperatures and sunshine above average; the second part was very wet with temperatures and sunshine below average.

Rainfall totalled 124.7 mm (188%) and [217%] of average. It was the wettest May since 2003 that with 148.3 mm was the wettest since before 1928. Since 1928 it ranks 4th wettest. May along with April are on average the driest months of the year. January was the only month so far to be drier than average. Rainfall for the year totalled 503.1 mm, the second wettest January to May period. Wetter was 1995 that had 513.1 mm, but it exceeds the 497.7 mm recorded in 2000, the wettest year. The wettest day was on the 21st with 25.5 mm, but the 19th also had 22.8 mm. But, there were 8 completely dry days scattered through the month. Rain days (>= 0.2 mm) were 21 (+6.1) while wet days (>=1 mm) were 17 (+6.3). Significantly there were 10 days that had 5 mm, or more (+5.3).

Sunshine duration at RAF Valley totalled 175.5 h and was (92%) and [91%] of average using Kipp & Zonen equivalent values). It was lowest since 2003 (143.6 h) and before that 1999 (158.0 h). The sunniest day was on the 5th with 13.8h. There were 3 sunless days, but 6 days had 10 h, or more sunshine.

The mean temperature 11.6C was very close to average (-0.1) and [+0.1]. This hides the fact that the beginning of the month saw some above average temperature with 24.7C (+1.4) on the 4th, the highest of the month and 22.2C on the 12th. These were the only days >=20C. The mean maximum was 15.3C (-0.2) and [-0.7]. The mean minimum was 7.9C (0.0) and [+0.9]. The highest minimum was 16.3C on the 4th and lowest 2.1C on the 23rd. The latest low minimum in May I have recorded here was 1.8C on 30th May 1985. There was 1 ground frost with a minimum of -1.2C, also on the 23rd, and was the latest date in May since before 1987. The mean soil temperature at 30 cm depth was 13.3C and (-0.2) of average.

Thunder was heard on the 4th and ice pellets fell on 2 days the 22nd and 23rd. The 18th saw gale to severe gale force winds while the 17th had strong to near gale-force winds.

June 2006

Dry, very warm and sunny

Dry and sunny with record early temperatures at the beginning, duller with lower temperatures and a little rain in the second half.

With 26.7 mm of rainfall it was a dry month. Just 36% of the decadal average and 40% of the 1971-2000 average there were 16 (+5.9) dry days. Rain days were 12 (-3.8) and wet days 8 (-3.0). There were 2 days with 5 mm, or more. The wettest with 5.5 mm was on the 24th and 5.0 mm on the 20th, both in the wetter second half of the month. The first 10 days were dry and rainfall to the 16th was only 2.9 mm. The soil surface at 09 GMT was dry on 18 mornings. It was the driest June since 1988, in that year there were only 19.8 mm, and the 6th driest in records since 1929. The driest June was in 1942 having only 8.4 mm.

Evaporation measured by the Piche evaporimeter was 58.2 mls (+13.9) and was the highest in June records since 1996. Evaporation by lysimeter was 71.2 mm and was on the average calculated with 9 years from 1997.

Maximum and minimum mean temperatures were 2.0C above the 1971-2000 average. The mean of 15.6C (+1.7) and [+2.0] was highest since before 1979 when records were started at this station beating the previous high of 15.2 seen in 1992. After a run of 9 Junes with negative anomalies (1994 to 2002 except 2000 with a small positive) it is the 4th consecutive with a large positive anomaly (see graphic). The highest daily mean was 23.0C on the 10th, the highest on record in June, with 21.5C recorded on 9th. The lowest mean of 11.9C on the 14th was just 0.1C lower than the 12.0C of June 1988. The mean maximum was 19.7C (+2.3) and [+2.0] highest since 1992 (20.0C) ranked 4th highest. The highest maximum of 28.6C (+4.1) on the 9th was the highest reached on this date in the year at this station; the next day reached 18.5C. Both were highest since the 29.0C in 2000 and fell short of the 29.2C of 29th June 1992. The lowest maximum 14.4C (+1.4) was on the 26th and ranked second highest to the 15.6C on the 8th June 1988. The mean minimum of 11.5C (+1.7) and [+2.0] was highest in June since before 1979. It exceeded the previous highest of 11.3C set in 2005. The highest was 17.4C (+2.8) on the 10th not quite reaching the 17.6C on the 19th in 2005. The lowest was 6.3C (+0.5) on the 1st of the month that also had the lowest grass minimum of 3.4C (+0.4). The mean soil temperature at 30 cm was 16.9C (+1.1).

It was a sunny month with 232.6 h of sunshine (145%) and [138%] recorded at RAF Valley on their Kipp & Zonen instrument. Using adjusted values for Anglesey from Campbell-Stokes instruments back to 1931 it ranked 6th highest and most since 1975 (252.0 h). The sunniest day was on the 14th with 15.5 h, in all 13 days received 10 h, or more. There were 3 sunless days and and another 2 had only 0.1 h. The sunniest June was in 1940 with 256.4 h (adjusted K & Z value); the least sunny was 1987 with 111.1 h.

The monthly mean wind speed at Valley was 9.7 mph that was equal lowest with 1993 and 9.0 mph in 1992. There were no gales reported with a maximum gust of 50 mph on the 20th. Thunder was heard in Llansadwrn on the 10th but there was no hail observed.

July 2006

A remarkably warm month with 9 records broken; sunshine above average and rainfall below average

A remarkable month with at least 6 records on my 28-year record at this station broken. The monthly mean temperature of 18.7C highest on record since 1979 beating the 19.7C recorded in 1983. It was [(+3.1)] of both the 10-y and 1971-2000 averages. It was also highest, equal with August 1995, of any month in the year. The maximum temperature of 32.6C on the 18th first broke the station's July record, but was overtaken by the absolute maximum of 34.9C (+9.8) on the 19th becoming the highest in July exceeding, by a big margin, the 31.2C on 14th July 2003 and the 32.8C recorded at RAF Valley in 1948. It was also a record high for any month on Anglesey exceeding the 33.0C recorded on 2 August 1990 here and on 5 August 2003 at RAF Valley by a huge +1.9C. The lowest maximum of 17.5C (+3.1) was highest too exceeding the 16.4C recorded in 1999 by +1.1C. The mean maximum was 23.5C (+4.5) and [+4.1] was the highest on record exceeding the 23.2C recorded in 1983. The mean minimum was 13.8C (+1.7) and [+2.1], but was not high enough to beat the previous highest of 14.1C in 1995. The highest minimum of 17.6C on the 20th equalled that recorded in 1995, but the lowest minimum 9.4C (+1.2) was the highest on record exceeding the 9.2C seen in 2003 and 2005. The mean soil temperature at 30 cm was 19.0C was highest on record since before 1990 exceeding the previous highest 18.5C in 1995.

Number of days with a maximum of 20C and 25C, or more, were 24 and 8 respectively 1 day each less than in 1989 (24,9). Days in 1990 were 21,10 while 1983 had 25,7 days. The spell of weather was unusual for the high temperatures experienced on the 18/19th but not for its length.

Rainfall was 26.1 mm (43%) and [41%] of average. It was wettest since 1999, that also had 26.1 mm, and ranked the 6th driest July in Llansadwrn since 1928. The wettest day was on the 8th with 11.0 mm. There were 20 (+8.5) dry days and 8 (-6.9) rain days (>=0.2 mm). Wet days (>=1.0 mm) were 7 (-3.6) and there was only 1 day that exceeded 5 mm. Evaporation was high with the Piche evaporimeter recording 76.9 ml the highest on record in any month since 1996. The lysimeter measured 99.5 mm potential evapotranspiration and a negative potential water balance of 73.4 mm. There was a potential water surplus of 10.6 mm shown on only 4 days 8/10 and 31st while the potential water deficit was 84.0 mm. Soil moisture had fallen to 24% (dm) from a saturated water percentage around 70% at the end of April. The permanent wilting percentage is around 15% for the local soil and some parts probably were approaching this value. Leaves on some shallow rooted plants, grass and sapling trees were withering although most mature trees were unaffected.

Sunshine duration recorded at RAF Valley was 277.8h and was the sunniest July since 1955 that had 284.4 h (using estimated equivalent Kipp & Zonen values) and ranked 2nd on the Anglesey record since 1930. The sunniest day was on the 14th with 15.0h, but the 15th saw 14.9h and the 11th 14.5h. In all 12 days had 10h, or more and none were sunless. Estimated values for Llansadwrn indicated a little less sunshine with 1 sunless day.

Thunder was heard on 3 days (3,5 and 20), but no hail was observed.

August 2006

Below average temperatures and sunshine, and above average rainfall made for a marked contrast to July

What a contrast to July. Except for 3 very wet days rainfall was fairly evenly distributed through the month. There were only 4 (-6.9) dry days with 21 (+5.2) rain days (>=0.2 mm). Wet days were 13 (+1.0) and there were 6 (0.0) that accumulated 5 mm, or more. Total rainfall was 102.3 mm (124%) and [127%] wetter than 2005 and wettest since 2004 and ranked 27th since 1928. The wettest day was on the 30th having 22.8 mm while the 30th had 14.8 mm and the 18th 14.0 mm.

The mean temperature of 15.4C was (-0.7) of the decadal average but was on the average of the 30-y 1971-2000. It was equal lowest since 2001 and ranked 14th since 1979. One day hit the 25C barrier with 25.2C (-1.1) on the 6th and 9 reached 20C, or more. The mean maximum was 18.7C (-1.0) and [-0.6] and the mean minimum 12.0C (-0.5) and [+0.6]. The lowest minimum was 9.3C (+0.7) on the 25th while the lowest grass minimum 5.0C(-0.3) was on the 8th.

Sunshine duration recorded at RAF Valley was 146.6 h, 91% of the decadal average and 89% of the 1971-2000 average. It was lowest since 2004 and ranked 27th lowest on the Anglesey record since 1930. The sunniest day was on the 7th with 12.5 h and the 24th with 10.5h the only other day to see more than 10h. There were 3 sunless days.

September 2006

Record average temperatures, sunshine was above and rainfall below average, but stormy

Despite storms beginning and end of month there was fine sunny weather in the middle

It was the warmest September since 1949 in Britain with a provisional mean of 15.4C +3.1 of the long-term-average, well up from the 14.7C recorded in 1949. At this station 10 temperature records going back to 1979 were broken. The mean temperature here, highest on record, was 16.3C and was +1.9 on the decadal average and a massive +3.0C on the 1971-2000 climatological average, comparable to July. The highest mean of 21.2C on the 21st was one that did not beat the previous highest of 21.9C set in 2005, but the lowest mean of 13.0C on the 7th exceeded the previous 11.8C of 1999. Only 5 days had a mean of <15.0C. The mean maximum was 20.0C (+2.3) and [+3.0] and beat the previous highest 18.8C of 1991 by more than a degree. The highest maximum was 26.2C (+2.0), the only day to exceed 25C, was below the record 28.0C set last September, 2005. The highest minimum was 16.3C (+1.1) on the 6th was also a record beating the previous 16.2C recorded in 2000 and 2005. The mean minimum of 12.6C (+1.6) [+2.9] was also highest on record beating the 11.6C set in 1999. The lowest minimum was 9.0C (+2.5) on the 8th exceeded by a degree the previous highest 8.0C in 2001. The mean grass minimum 10.0C (+1.4) was the highest since records began in 1986 and the lowest 5.5C exceeded the 5.0C recorded in 1989.

Days of 20C, or more, in September numbered a record 16 beating the previous highest 12 in 1998. For the year January to September the number of days with 20C, or more, reached 66 equalling the previous highest recorded in 1990. Days with 25C, or more, with 1 more in September crept up to 12 in total ranking the year only 5th since 1979; 1990 had 20 days a record unlikely to be broken in 2006 while 1995 saw 15 days .

Rainfall totalled 85.6 mm and was ( 81%) of the decadal average but [93%] of the 1971-2000 average, equal lowest with 2005 since 2002 that had only 23.0 mm. It was wettest at the beginning of the month when 39.5 mm fell in the first 3 days. This included 20.0 mm on the 4th, the wettest day. Another significant fall was on the 20th with 14.8 mm falling at this station, but 2 other local stations on the coast to the NE of here reported 23 and 25 mm. There were 10 (+0.1) dry days and 17 (+1.1) rain days while wet days were an average 12. Evaporation by lysimeter measured 25.8 mm and there was a water balance of 59.8 mm. Soil moisture was 45% dry matter having recovered from the low of 20% in July but with close to average rainfall in August and September is still well below its 70% saturation water percentage. Grass growth, also up from a summer low of 1.4 g g/m, fell from 5.4 g/m² at the beginning of the month to 3.2 g/m² in the drier warm weather. With higher than average temperatures continuing to the end of the month, and some more rain, grass growth measured up to the beginning of October was 7.9 g/m^2, comparable with the flush of spring growth of 8.2 g/m² in April. Despite the September growth the total net production of 805 g/m² in 2006 was still less than that seen in 2004 (1500 g g/m^2,) and 2005 (1000 g/m²), growth being primarily limited by the cold late spring and the hot dry spell in July.

Sunshine duration at RAF Valley was 155.1 h (121%) and [123%] with 1 sunless day while here, in the cloudier SE corner of the island, the solar radiation measurement suggested 132.5h duration with 2 sunless days. Valley sunshine was highest since 1996 and ranked 11th sunniest on the Anglesey record since 1930. The sunniest day was 11.9 h on the 8th.

October 2006

A warm month, but not the warmest October, rainfall and sunshine above average

The mean temperature for the month was 12.8C (+1.6) and [+2.2] equal to 2005, but ranked 4th since before 1979. Highest was 13.2C in 2001 with 1995 on 13.1C. The mean minimum of 9.4C (+1.2) and [+2.1] was similarly ranked 4th with the highest 10.7C recorded in 2001. It was lower than 2005, that had 10.0C, while the highest recorded here was 10.7C in 2001. The lowest minimum was 6.3C (+2.9) and ranked 2nd highest behind 6.4C recorded in 2001. The highest minimum of 12.0C (-0.9) was the 7th lowest observed since before 1979. The mean maximum 16.1C was, however, highest on record since before 1979 beating 1995 that had 16.0C. The absolute maximum 19.9C (+0.2) on the 18th not reaching 20C did not add to the total of 20C, or more, for the year. The total for 2006 still stands at 66 equalling the total set in 1990 (see September report above). The highest maximum was way behind the 24.1C recorded in 2005. The lowest maximum 12.5C (+2.5) ranked 2nd highest behind 1995 that saw 13.4C.

Rainfall totalled 155.9 mm and was 109% of the decadal average, but 139% of the 1971-2000 average, and was lowest since 2003. The wettest day was on the 25th with 35.1 mm. There were 7 (+0.1) dry days while there were 21 rain days (0.2 mm, or more) spot on the average. Wet days (1.0 mm, or more) also numbered 21 these were (+4.2) of the average. Days with 5 mm, or more, totalled 10 (+1.0). Despite the Piche recording 32.9 mls evaporation the lysimeter PE was only 4.8 mm.

Sunshine duration at RAF Valley was 116.4h and (121%) of average, sunniest since 1994 and the 6th sunniest October on the Anglesey record since 1930. Three days had more than 9h sunshine; the sunniest day was on the 9th with 9.8h duration, the 14th had 9.6h and the 15th 9.1h. There were 4 sunless days with another only seeing 0.1h duration.

November 2006

Temperatures continued above average, sunshine was above and rainfall below average

The beginning had most settled weather with lowest temperatures but most sunshine, while the end was dull and often stormy with rain and ice pellets

The mean temperature was 8.6C, highest since 2003, and (+0.6) and [+1.4] of the decadal and 30-y average respectively. The highest mean was 11.4C on the 15th and the lowest 6.0C on the 21st. The mean maximum 11.3C, also highest since 2003, was (+0.7) and [+1.3] of average. The highest maximum 14.2C (-1.1) was on the 15th while the lowest 7.5C (+1.1) was on the 21st. The mean minimum 5.9C was highest since 2004 and was (+0.4) and [+1.4] of average. The lowest minimum 0.9C (-0.4), a little below average, was on the 3rd, there being no air frosts. The mean grass minimum was 3.2C (+0.6) and the lowest -2.4C (+0.9) was on the 3rd, there were 3 ground frosts 5.8 days less than average. Soil temperature at 30 cm depth averaged 9.5C (+0.5). The monthly means reflect the increase in temperature over the past decade compared with the 1971-2000 average.

Rainfall totalled 121.6 mm, 4.8 inches in old money, but below average particularly compared with the decadal (83%), it was [97%) of the 30-y average. November, the wettest month of the year, on 54 occasions since 1928 had 100 mm, or more. It was wetter on the north-west coast, at RAF Valley where 127.6 mm was recorded. There have been some very wet Novembers in Llansadwrn during the last 10 years including the wettest, in 2000, that had 250.5 mm. The largest fall this year was 25.3 mm on the 19th. There were 6 (2.6) dry days and 21 (-0.2) rain days. Wet days numbered 17 (-1.6) while days having 5 mm, or more, were 8 (-2.0).

Sunshine duration at Valley was 58.4 h (112%) ranking 35th. The sunniest day with 7.9h on the 1st, but the 2nd had 5.9h and the 3rd 4.8h. With 4.7h on the 6th and 4.5h on the 9th it was a very sunny first half of the month with a total of 34.3h, the second half had only 24.1h. It was even sunnier in Llansadwrn, the estimated sunshine duration (Kipp & Zonen) was 63.3h. There were 7 sunless days.

It was a very windy month with 5 gales reported at RAF Valley. The monthly mean wind speed (mws) was 19.7 mph (+4.0) [+3.3] of average. On the 30th the mws was 39.1 mph, gale force 8. The highest gust was 71 mph on the 19th.

Thunder was heard on 3 days (+2.1) and there were 8 days (+2.7) on which ice pellets fell, all in the second half of the month. Gales were recorded on 5 days.

Autumn 2006

Autumn was the warmest on record since before 1979. The mean of the months September, October and November was 12.6C (+1.4) and [+2.2] of average beat last year's highest of 11.7C by a huge 0.9C. The mean maximum of 15.8C beating last year's 14.7C and mean minimum of 9.3C beating the 9.0C of 2001 were highest on record.

The graph shows the mean temperatures and smoothed plot over the 28-years of station records. Fitted to a linear regression the temperature significantly increases over the period an indication the warming trend that has taken place in recent years.

The histogram shows the mean anomaly (differences from the 1979 -2006 mean) over the same period. Since 1993, that was the coldest Autumn in the records, there have been a remarkable 8 years with positive anomalies of 0.5C, or more, culminating in 2006 with an anomaly of 1.9C.

Rainfall totalled 363.1 mm 92% of both the decadal and 30-y averages. It ranked 47th driest since before 1928. The driest autumns were 1945 with 201 mm and 1955 with 202 mm. The wettest was in 2000 and that had 612 mm.

Sunshine duration at Valley totalled 329.9 h (Kipp & Zonen), 118% (corrected Kipp & Zonen data, see below) of both the decadal and 30-y averages , and ranked the 5th sunniest autumn on the Anglesey record since before 1930. It was sunniest since 1995 which was the sunniest autumn on record with 337.5h (Kipp & Zonen corrected) or 380.9h (Campbell-Stokes original instrument).

December 2006

Record mean temperature, wettest since 1964 and 2nd wettest since before 1928, it was windy too

The beginning was very wet and windy with frequent hail, a quiet, dry often sunny spell lasted almost to the end before it turned, wet and windy again.

The monthly mean temperature was 6.9C (+1.1) and [+1.4] of average, this was the highest since before 1979 when I started observations at this station. The highest daily mean 11.2C on the 14th was not a record as it has been exceeded 4 times, the highest 12.0C in 1985. The lowest mean was 2.7C on the 24th has been exceeded twice, the highest 3.5C in 1988, and there have been many lower values (lowest -2.6C in 1995). The mean maximum of 9.2C (+1.0) and [+1.3] was equal to that seen in 1998 and 1994, the highest 12.4C (-0.1) was on the 29th and fell far short of the highest 15.2C recorded in 2002. The lowest maximum 4.0C (-0.1) was on the 24th. So while extremes were not outstanding 11 days had 10C, or more. The mean minimum 4.7C (+1.1) and [+1.6] was highest since 1968 that had 5.6C. The lowest 1.3C (+3.7) was on the 24th so there were no air frosts (-4.5) in December for the first time since records began in 1979. One had been recorded in 3 years, in 1988, 1997 and 2004. The lowest grass minimum was -2.4C (+4.5) and there were 10 days with frost (-4.3). The mean temperature of the soil at 30 cm was 7.4C, highest on record, and there was not a day that fell below the 5.6C (42F) an arbitrary temperature thought necessary for plant growth.

Overall it was a wet month with 215.7 mm (185%) and [188%] of average. It was the largest December rainfall ranking 2nd only to the 242.1 mm recorded at Gadlys Cottage and 235.7 mm at Treffos in 1964, those being the most in Llansadwrn since before 1928. It even exceed the 153.6 mm recorded in December 2000, the wettest year on record in Llansadwrn. The largest fall of 35.7 mm was on the 10th, but 33.2 mm fell on the 2nd. There were 12 days (+3.2) with 5 mm, or more and 17 (+0.8) wet days (1 mm, or more). There were 19 (-1.2) rain days (0.2 mm, or more) and a surprising 8 days (+1.4) were dry. Another day had no rain, but recorded 0.1 mm of dew, and another 3 saw only traces.

Sunshine duration at RAF Valley was 41.1 h (88%) making it a rather dull month with 9 sunless days and lowest since 2003 based on Kipp & Zonen corrected data. The sunniest day was on the on the 11th with 5.2h, but the 19th had 4.4 h and the 22nd 4.5h.

It was a windy month with gales on 13 days in Llansadwrn and 12 at RAF Valley. The mean wind speed for the month was 20.0 mph, but the 24-h mean on the 3rd was 43 mph with a maximum gust of 77 mph.

Annual 2006

The change to a warmer climate continued with the highest annual mean recorded. Rainfall and sunshine were above average

The annual mean temperature of 10.8C was (+0.5) and [+0.95] of the decadal and 30-y averages. It was the highest recorded since records began in 1979 exceeding the previous highest 10.7C recorded in 1990 and 1997.

The graph shows the mean plotted over the 28-years of station records together with a smoothed graph. Fitted to a linear regression the temperature increases over the period by over 1C, an indication the warming trend that has taken place in recent years. The histogram shows the mean anomaly over the same period (differences from the 1971 -2000 climatological mean). Since 1979 there have been 11 years with an anomaly of +0.5C, or more.

The annual mean maximum was 14.1C (+0.6) and [+0.9] of average and ranked 3rd behind 1989 with 14.3C and 1990 with 14.4C. . The highest maximum of 34.9C recorded on 19 July was the highest recorded at this station and exceeded the 33.0C recorded on 2 August 1990 here, and on 5 August 2003 at RAF Valley by a huge +1.9C. The highest lowest maximum of 17.5C recorded in July was the highest recorded here in any month of the year and exceeded the 16.5C of August 2000.

The number of days with 20C, or more, reached 66 equalling the previous highest recorded in 1990. Days with 25C, or more, numbered 12 ranking the year only 5th since 1979; 1990 had an unbroken record number of 20 days while 1995 had 15 days .

The annual mean minimum 7.6C was (+0.4) and [+1.2] of average was the highest on record exceeding the 7.5C of 1998 and 2005. The lowest minimum was -5.0C on the 3rd March which also saw the lowest grass minimum temperature of -12.4C recorded at this station since 1985.

Rainfall for the year totalled 1237.0 mm (109%) and [120%] of average and ranked the 13th wettest since before 1928. But, it was wettest only since 2004 that had 1320 mm and less than the 1484 mm recorded in 2000, the wettest year on record, and 1999 that had 1286 mm. In comparison Capel Curig reported a provisional total of 2892 mm for the year. The wettest month in Llansadwrn was December with 215.7 mm while the driest was June with 26.7 mm. The greatest fall was 35.7 mm on 10 December. After a somewhat wetter 1950/60's and drier 1970's there has been a trend of increasing rainfall through into 21st Century

After 2 dull years sunshine duration total at RAF Valley was 1649 h (Kipp & Zonen electronic instrument) (118% of average) equivalent to 1901 h had the Campbell-Stokes instrument still been in use. It was sunniest since 1975 and ranked the 3rd sunniest on the Anglesey record since 1930 using Kipp & Zonen corrected values. The sunniest day was on the 14th June having 15.5h duration. There were 54 sunless days. Estimated sunshine duration in cloudier Llansadwrn was 1486 h with 67 sunless days.

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Monthly data 2006

Llansadwrn (Anglesey): ~ Anomaly based on the 1996-05 average ------------------------ ------------------------ Air temperatures (C) Mean max Mean min Mean Anomaly~ High max Date Low max Date High min Date Low min Date Grass min Date Atmospheric moisture means RH (%) Dew point (C) Soil temperatures (C) 5 cm 10 cm 20 cm 30 cm 50 cm 100 cm Rainfall (mm) Rain tot Rain % ave~ Days, dry Days >=0.2 Days >=1.0 Days >=5.0 Max fall Date Evaporation Piche (mls) Lysimeter PE (mm) -3.1 10.1 Weather (days) Air frost Ground fr Sl/snow Sn lying Thunder Hail <5 mm Hail >=5 mm Fog at 09h Gales Wind direction at 09h (days) N NE E SE S SW W NW Calm Autographic records Rain Frost Cloud cover at 09 GMT Mean (%) Solar radiation and sunshine duration Llansadwrn Sol rad (mv h) * ESD (h) Sunless days Valley Sunshine (h) Average % ~ Sunless days # C-S (h) ------------------------ ------------------------

width=60% border="0" cellpadding="30" cellspacing="0"> valign=middle> Monthly weather data for 2006. --------------------------------------------------------------------------------------- Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year --------------------------------------------------------------------------------------- 7.5 7.3 8.2 12.6 15.3 19.7 23.5 18.7 20.0 16.1 11.3 9.2 14.1 2.6 2.7 2.5 5.0 7.9 11.5 13.8 12.0 12.6 9.4 5.9 4.7 7.6 5.1 5.0 5.3 8.8 11.6 15.6 18.7 15.4 16.3 12.8 8.6 6.9 10.8 -0.5 -0.8 -2.0 -0.1 -0.1 +1.7 +3.1 -0.7 +1.9 +1.6 +0.6 +1.1 +0.5 10.8 10.6 12.7 16.2 24.7 28.6 34.9 25.2 26.2 19.9 14.2 12.4 34.9 13 14 26 25 4 9 19 6 21 18 15 29 19 Jul 2.5 4.1 2.3 6.4 10.0 14.4 17.5 14.9 15.1 12.5 7.5 4.0 2.3 5 1 2 4 22 26 8 15 14 31 21 24 2 Mar 9.4 8.0 9.3 9.5 11.3 17.4 17.6 16.9 16.3 12.0 10.9 10.6 17.6 19 13 27 25 17 10 20 6 6 6 30 14 20 Jul -2.2 -1.6 -5.0 -0.6 2.1 6.3 9.4 9.3 9.0 6.3 0.9 1.3 -5.0 8 10 3 10 23 1 13 25 8 24 3 24 3 Mar -6.5 -5.6 -12.4 -4.0 -1.2 3.4 6.2 5.0 5.5 1.7 -2.4 -2.4 -12.4 30 10 3 5,10 23 1 13 8 7,15 4 3 10 3 Mar 88 87 88 82 84 79 75 89 85 93 86 92 86 2.3 2.2 2.7 5.6 9.0 12.3 14.6 13.0 13.4 10.7 11.3 5.2 8.5 3.7 3.8 4.8 9.2 13.1 18.2 20.6 16.4 15.6 11.7 7.3 5.9 10.9 4.2 4.2 4.9 8.8 12.2 16.6 18.8 16.0 15.2 12.1 7.9 6.3 10.6 4.8 4.9 5.4 9.3 12.5 16.5 19.0 16.7 15.9 13.0 8.8 7.0 11.2 5.0 5.2 5.7 10.0 13.3 16.8 19.0 17.3 16.5 13.6 9.6 7.5 11.6 6.0 5.8 6.1 9.9 13.2 16.4 18.5 17.5 16.6 14.2 10.4 8.1 11.9 7.3 6.8 6.8 9.4 12.4 15.0 17.0 16.8 16.1 14.5 11.6 9.3 11.9 74.6 80.5 139.9 83.4 124.7 26.7 26.1 102.3 85.6 155.9 121.6 215.7 1237.0 78 77 225 110 188 36 43 124 81 109 83 185 109.2 15 8 3 11 8 16 20 4 10 7 6 8 116 12 13 23 16 21 12 8 21 17 21 23 19 206 9 9 20 12 17 8 7 13 12 21 17 17 162 8 5 11 7 10 2 1 6 6 10 8 12 86 18.6 20.5 19.1 15.5 25.5 5.5 11 22.8 20.0 35.1 25.3 35.7 35.7 10 23 27 18 21 24 8 30 5 25 19 10 10 Dec 24.8 25.9 27.9 36.5 43.9 58.2 76.9 35.1 46.3 32.9 33.3 24.2 465.9 7.8 32.0 40.8 71.2 99.5 41.1 25.8 4.8 9.6 10.9 350.5 6 2 8 2 0 0 0 0 0 0 0 0 18 18 12 13 8 1 0 0 0 0 0 3 10 65 0 2 6 2 0 0 0 0 0 0 0 0 10 0 0 6 0 0 0 0 0 0 0 0 0 6 0 0 2 1 1 1 3 1 0 0 3 4 16 1 5 10 3 2 0 0 0 0 1 8 6 36 0 0 0 0 0 0 0 0 0 0 0 3 3 0 0 1 0 0 0 0 1 0 0 0 0 2 5 1 2 0 1 0 1 0 4 2 3 13 32 1 3 1 2 2 1 2 8 2 0 2 1 25 3 4 1 6 3 6 2 1 1 1 0 1 29 3 6 7 0 3 0 1 0 0 3 0 3 26 3 1 5 1 2 2 6 0 7 5 2 2 36 5 3 3 2 9 11 11 1 10 7 11 8 81 3 3 7 6 5 6 3 4 6 7 6 8 64 3 4 2 6 3 1 2 6 1 5 6 2 41 3 1 4 5 3 2 0 7 0 2 3 4 34 7 3 1 2 1 1 4 4 3 1 0 2 29 of rainfall and frost duration (h) 53.0 64.8 132.8 60.2 103.2 37.0 23.4 84.8 46.4 71.8 78.8 106.8 863.0 49.2 5.0 74.7 5.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 134.2 65 79 80 79 73 73 61 84 64 70 80 77 74 88.2 151.9 251.9 500.7 532.2 637.8 683.8 396.7 360.3 187.5 108.7 45.6 3945.3 57.7 75.2 102.7 171.1 179.8 208.8 221.5 142.5 132.5 85.0 63.3 46.0 1486.1 7 10 12 2 2 5 1 4 2 5 7 10 67 77.3 84.3 93.2 190.7 175.5 232.6 277.8 146.6 155.1 116.3 58.4 41.1 1648.9 127 106 78 134 92 145 180 91 121 121 112 88 118 7 10 5 2 2 3 0 3 1 5 7 9 54 82.9 90.2 100.5 214.5 208.4 281.9 333.5 172.3 177.7 130.4 64.0 44.3 1900.6 --------------------------------------------------------------------------------------- Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year ---------------------------------------------------------------------------------------

Notes:

^* ESD is an experimental Estimated Sunshine Duration. It was calculated using a relationship derived by fitting Llansadwrn solar radiation and Valley sunshine duration data to a linear regression equation .

# Valley sunshine duration, since August 2005, has been measured using a Kipp & Zonen electronic sensor. This gives sunshine durations that are different to the previous Campbell-Stokes instrument. A conversion factor ¹ has been applied to estimate what the Campbell-Stokes (C-S) duration might have measured for comparison. The electronic sensor measures less sunshine than the Campbell-Stokes instrument, it varies throughout the year and is about 20% less in summer and 7% less in winter. Averages have been computed using estimated equivalent Kipp & Zonen sunshine durations.

References

1: Prior J. (2006). Sunshine measurement. Weather 61, p. 77.

2: Kerr A. & Tabony R. (2004). Comparison of sunshine recorded by Campbell-Stokes and automatic sensors. Weather, 59 (4), pp. 90-95.

Acknowledgement

I am grateful to Robert Jones, Observer/ Admin. Officer at the Met Office RAF Valley, for supplying the quoted Valley observations.

Page first dated 2 February 2006
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Llansadwrn (Anglesey) Weather: Monthly and Annual Summary for 2006