Llansadwrn (Anglesey) Weather:
Monthly and Annual
Summary for 2003
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Llansadwrn (Anglesey) Weather:
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Rainfall of 82.2 mm was 82% of average ( 65.4 h duration) ranking it the 27th driest January since 1928 It was the driest since the 44.0 mm in 2001. There were 3 days with more than 10 mm. The wettest day was on the 24th with 15.6 mm but the 2nd had 13.1 mm and the 16th 12.2 mm. The number of dry days was 8 (+0.9) and there were 18 rain days (0.2 mm or more). There were 14 (-1.2) wet days (1.0 mm or more) and 6 (-0.4) days had 5.0 mm or more.
The month had a near average mean temperature 5.2C (-0.3) but the lowest daily mean of 0.3C on the 7th was the lowest in January since the -1.7C in 1997. The mean maximum was 7.3C (-0.7) with 6 days with 10C, or more. The highest maximum was on the 26th with 12.2C and the lowest on the 7th with 1.7C but the 30th was close with 1.8C. The mean minimum was 3.1C (+0.2) and was +0.7 on the 1971-2000 average despite some cold days between the 5th - 11th and 23rd - 24th. The lowest minimum of -2.9 (-0.4) was on the 8th and there were 6 (+1.0) days, or 64.8 h, with airfrost. There were 10 days (-3.7) with ground frost, the lowest grass minimum -7.3C (-0.7) being on the 5th with -6.7C being seen on the 8th. The mean soil temperature at 30 cm was 5.4C (+0.4) with 19 days with 5.6C or more (the temperature thought necessary for plant growth). Evaporation was a little below average with PE (potential evapotranspiration) of -1.4 mm (-2.9) and 29.6 ml (-1.1) evaporated from the Piche evaporimeter.
There were 5 days (+1.6) with hail <5 mm ranging from snow grains about 1.5 mm (small hard white grains of ice) and 6-pointed flat ice crystals up to 2 mm diameter on the 3rd; snow pellets 2 - 4 mm diameter (white compressible and conical shaped) on the 30th; and ice pellets 3 - 5 mm diameter (translucent layered ice) on the 22nd and 28th. Snow was seen on 2 days (average) , a flurry on 3rd and snow that almost covered the ground in the early hours of the 30th that melted to about 30% cover by 0900 GMT. Thunder was not heard in the month.
There were 2 days with gale force 8 and 9 wind on either side of midnight on the 16/17th.
Contrasts in rainfall and temperature. The middle of the month was particularly dry, sunny and cold.
A month of contrasts with 23.5 mm rainfall on the 8th and 7.1 mm on the 28th, otherwise it was fairly dry. In the middle of the month it was very dry when it was also cold. But the month saw 10 days with a maximum over 10C, and the 14.9C (+2.7) on the 26th ranking 3rd in February on record. It was just 0.1C below the 15.0C of 1998, but somewhat off the 17.2C seen in 1985. The month also saw 9 airfrosts (the most since the 12 in 1996) and 21 ground frosts (the most since the 22 of 1991). The lowest air temperature was -3.1C (-2.0) on the 15th with -3.0C seen on the 18th. There were 2 nights when -9.0C (-4.2) was recorded on the grass, the lowest in February since the -11.0C in 1985 and -10.0C in 1986. The month saw 8 days on which the temperature range exceeded 10C (6,10,17,18,20,21,24,25). The largest were 12.5C on the 17th and 12.7C on the 20th. In contrast there were 7 days on which the range was less than 5C (2,4,7,8,11,26,27). The smallest were 1.7C on the 2nd and 1.5C on the 11th.
Monthly temperatures also were contrasting with the mean maximum 9.0C (+0.5) and the mean minimum 1.8C (-1.3). This gave a mean of 5.4C (-0.4) but (+0.1 on the 1971 -2000 average). The mean temperature of soil at 30 cm depth was 4.9C (-0.8) the coldest since 1996. The surface soil of the bare plot was frozen on 5 mornings and the lowest temperature seen at 5 cm depth was 0.0C on the 19th. There were 20 days when the temperature at 30 cm was less than 5.6C while only 8 reached 5.6C, or more ( the temperature thought necessary for plant growth).
Rainfall was 45.5 mm (43% of average but 60% of the LTA) the driest February since 1993 (30.8 mm) in which the month of May had 140.2 mm, I hope the pattern does not repeat itself! It was the 20th driest February on record here since 1928. There were 12 dry days (+6.3) (frost deposition on 2 days was not counted as rain for this purpose). Rain days (0.2 mm, or more) numbered 13 (-6.3) while there were 10 (-4.6) wet days (1.0 mm, or more). There were just 2 days with 5.0 mm, or more on the 8th and 28th.
Evaporation from the Piche evaporimeter 33.9 ml (+7.6) was the highest recorded over 7 years. The 18/19th saw some low relative humidity values with a low of 37% on the 19th. On the 19th evaporation from the Piche evaporimeter, housed in the Stevenson screen, for the 24-h was 3.5 ml. In the ground evaporation measured by the lysimeter over the month was a small negative value (-0.8 ml), not unexpected because the soil was cold and often frozen.
There were 4 days with small hail, all at the beginning of the month. Ice pellets were seen on the 2nd and 5th while snow pellets were seen on the 2 - 5th. Sleet fell on the 2nd and snow on the 4th. No thunder was heard.
Winter
; "Click for graph of number of airfrosts in winter. © 2003 D.Perkins."){kind=small}
After the spell of cold weather in February the number of airfrosts this winter (climatological winter being December to February) reached 17. I have plotted the number observed in Llansadwrn since I began records in 1979. The plot shows a generally decreasing number recorded since 1979, a likely consequence of the warming trend in recent years?
All 3 winter months had below average rainfall with the total 240.8 mm (-92.0). It was the driest since 1996 (151.0 mm) and 1997 (218.7 mm). Mean winter temperatures were all above average: mean maximum 8.1C (+0.2); mean minimum 3.0C (+0.5) and the mean 5.6C (+0.4).
The 7/8th were wet and windy with a total of 26.3 mm rainfall on fronts associated with a very deep Atlantic low. With local soils still up to field capacity water was standing and forming pools on nearby fields. Runoff water made roads awash especially in the mountains, Capel Curig reported 80 mm in 12-h on the 8th, and driving was difficult. From the 12th it was dry with little or no rain until the end of the month. Total rainfall was 51.3 mm (72%) but 15.8 mm occurred on the 1st April before 09 GMT and by convention had to be credited to the 31st March. With this rainfall it was the 29th driest March on record since 1928. Without it would have been the 12th driest! There were 16 dry days (+6.4) and another 4 days with trace amounts making 20 days in all. Rain days (0.2 mm, or more) were 10 (-6.5) and wet days (1.0 mm, or more) were only 5 (-6.4) of which 3 were 5 mm or more (-1.7).
; "Click for histogram of monthly mean maximum temperature anomalies in March: © 2003 D.Perkins."){kind=small}
There were many warm days throughout the month; 25 days had maximums of 10C, or more, and 7 had 15C, or more. The warmest was on the 28th with a maximum of 17.4C but the 15th and 27th also had more than 16C. These were not unusual as the 17.4C ranks 5th highest with 20.0C seen in 1990 and 20.5C in 1997. The monthly mean maximum, however, was 12.3C (+2.2) and was the highest on record since 1979. In contrast minimum temperatures were 'middle of the road' with a mean of 3.9C (-0.1). There was 1 (-1.0) minimum of -1.5C on the night of 13/14th with 10.6h airfrost and 16 nights (+5.5) ground frost. Lowest was -7.0C recorded on the 14th while -5.0C and -5.7C were seen on the next 2 nights. The monthly mean was 8.1C (+1.1) and was warmest since the 8.4C in 1998 and ranks 4th on record. The temperature range on the 14th was 16.8C the largest in over 5 years; 16.5C was seen on on 18 June 2000. From an overnight minimum of -1.5C the temperature rose to a Föhn-enhanced 15.3C when the wind turned SE'ly (Valley did not see the Föhn and reported 13C but was credited as the highest in the UK). Humidity values were low, 37% here, with some stations in England reporting values down to 25%.
Evaporation measured by the Piche evaporimeter was 47.4 ml (+16.2) and the largest in March on record over 7 years. From the 10th PE (potential evapotranspiration) measured by lysimeter became more significant and ended the month with a reading of 22.9 mm. The PWB (potential water balance) was 28.4 mm.
The 8 - 10th were very windy with gales on the 8th and 9th. Ice pellets were seen on the 7th the only day with hail in the month (-2.0). Thunder was not heard but there was fog at 09 GMT on 2 mornings.
Overall a very warm month with the mean 10.3C ranking 2nd warmest since 1979 (10.6C in 1987). The mean maximum 14.5C (+2.2) was the 4th warmest while the mean minimum 6.0C (+0.9) was joint 3rd warmest. The 4 days 14 - 17th were very warm all with maximums above 23C. The highest 25.3C, on the 16th with a range of 15.3 C, was the warmest here on the 25-y April record. It became only the 117th temperature of 25C, or more, in ANY month in the year. The mean temperature in soil at 30 cm depth was 11.0C (+1.4) and was also the warmest on record.
Up to the 19th it had been a dry month with only 5.4 mm rain. From the 20th it turned wet with 17.4 mm on the 27th and 17.8 mm on the 29th. These 2 days accounted for over 50% of the 66.6 mm in the month. But it was the driest April since 1997 (30.8 mm). On the 10-y average the total was 89%, there having been some wet Aprils in the last decade, but it was 107% on the long-term average and 115% of the 1971-2000 average. There were 16 dry days (+6.8) while there were 12 (-4.9) rain days. Wet days numbered 10 (-3.8) and there were 4 days (-1.8) with 5 mm, or more.
With a number of sunny warm days and low humidities (lowest 45% and 44% at times on the 16/17th) evaporation was high. There were 53.0 mls (+16.2) evaporated from the Piche tube and 50.1 mm (+11.7) PE from the lysimeter. Although PWB (potential water balance) was negative near the middle of the month it ended at +16.5 mm.
No thunder was heard in the month but there were 3 falls of ice pellets seen on the 1st, 2nd and 30th.
For more information see these Wx-Watch pages.
The dry spell in March and up to 19th April 2003. Airfrosts in April. The high maximum temperatures in April.
; "Click for histogram of monthly rainfall anomalies in May: © 2003 D.Perkins."){kind=small}
It was a wet month and with 148.3 mm (229%) it was 258% of the 1971 - 2000 average. It was the wettest May on record since 1928, exceeding the previous record of 140 mm in 1993. It was only the 11th May in records to have 100 mm, or more. Rainfall duration was 100.1 h.
; "Click for histogram of accumulated monthly rainfall: © 2003 D.Perkins."){kind=small}
May (average 65 mm) , along with April (average 63 mm), is usually one of the drier months of the year. But this year, with 83 mm more than average, it was not. Rainfall accumulation for the year (Jan - May) was brought up to 394 mm exceeding the long-term average of 378 mm. It is well below the 475 mm accumulated in 2000, the wettest year.
Wettest day was on the 21st with 27.8 mm with the 3rd on 26.5 mm not far behind. The spell 1 - 4th accumulated 60.9 mm. There were 9 (+4.6) days with 5 mm, or more and 15 (+4.7) wet days (1.0 mm, or more). Rain days (0.2 mm, or more) numbered 22 (+8.3) and there were 6 (-7.3) dry days.
The monthly mean temperature 11.6C ended on the average. The mean maximum 15.0C was 0.5C below average while the mean minimum of 8.2C was 0.5C above. The 2nd, with 9.5C, was the only day with a maximum below 10C. The 28 - 30th saw a spell with maximums of 20C, or more. The warmest was the 30th with 24.8C (+1.6) ranked 5th on record. It was warmest in May since 1998 (24.8C) with 2002 on 24.7C. Warmest were the 26.4C in 1989 and 27.6C in 1990. The minimum of 14.0C, also on the 30th, ranked 3rd warmest to 17.0C in 2002 being equal to 2001.
There was no airfrost and only 1 ground frost -0.4C on the 3rd. There were 2 days (11 - 12th) with ice pellets but no thunder was heard.
Temperatures were above average with the mean finishing on 15.0C (+1.5). With few cold nights, due to absence of clear skies, minimum temperatures were above average. The mean minimum with 11.2C (+1.3) was warmest on record here since 1979. The warmest night was on the 26/27th with 14.4C, but this was no record with 15.9C being seen in 1982, 1986 and 1989. The coolest night was on the 20th with 8.5C and was 1 of only 4 below 10C. The mean maximum of 18.8C was 1.7C above average but only managed to rank 6th warmest. Warmest Junes were in 1988 and 1992 both with 20.0C. There were no really warm days (none >=25C) but there were 9 days with temperatures of 20C, or more. The highest 23.9C was on the 16th, but that was 1.3C below the average.
The mean grass minimum of 9.2C was +0.8C on the average. Lowest was on the 20th with 5.3C but 12 nights had 10C, or more. Overall warmer temperatures were also reflected in the soil where the mean, at 30 cm depth, was 16.8C and 1.3C above average.
Rainfall totalled 69.0 mm just 0.2 mm more than in 2002. The month finished close to the average (95%), or 104% of the 1971-2000 average. The first 28 days had 39.7 mm while the last 2 had 29.3 mm some 42% of the total. So you could say that most of June was dry! Driest spell was 5 days from 12 - 16th and these were also the sunniest. Number of dry days were 10 (-1.6) while there were 14 (-1.2) days with rain (0.2 mm, or more). Wet days (1.0 mm, or more) numbered 11 (+0.5) and there were 5 days (+0.4) with 5 mm, or more. Wettest day was the 29th with 20.5 mm, we just missed the heavy fall of 54.6 mm that fell at Red Wharf Bay and Pentraeth.
No thunder was heard and there was no hail observed.
A warm month with the mean 16.7C (+1.2) largely the result of cloudy nights that raised the mean minimum to 13.4C (+1.5). While there were some very warm days the mean maximum 19.9C (+0.8) reflected a cool start and end to the month. It was warmest, however, since 1999 (20.7C). On the 14th the maximum of 31.2C was the highest in July on my 25-year record, beating the previous 28.8C seen in 1989, and is the 4th highest on the Anglesey record. The warmest July day recorded on Anglesey is 32.8C in 1948 at RAF Valley. The highest temperature at this station is 33.0C recorded on 2 August 1990. The spell 12 - 19th was a remarkable period with days >20C all except the 17th that in low cloud, fog and rain kept below the 17.7C recorded at 09 GMT. The 3 days 14 - 16th saw 31.2C, 27.7C and 26.5C. In contrast the 4th with 14.9C was the coolest day of the month. Warmest nights were the 15th with 18.5C and 16th with 18.9C that also saw grass minimum temperatures of 15.0C and 15.6C. Highest means were 23.5C on the 14th (highest on record), 23.1C on the 15th (2nd highest on record) and 22.7C on the 16th (4th highest on record). All were warmest since the 22.9C in 1983. The mean minimum of 13.4C (+1.5) ranks 2nd warmest on 25-year record only beaten by the 13.5C in 1995. Lowest minimum was 9.2C on the 1st. The grass minimum mean was 11.7C (+1.4) with the coolest night 6.8C on the 12th.
It was generally a dull month with several days shrouded in low cloud and mist. At RAF Valley there were 137.9 h of sunshine but this was 30% lower than the long-term average. Sunniest day was on the 13th with 13.0 h with the warmest on the 14th having 9.2 h. But there were 9 days with less than 1 h with 5 of them sunless (3, 4, 17, 29, 31).
 "Graph of soil water content at Llansadwrn up to July 2003."){kind=small}
The month finished with 50.1 mm and was 89% of the 1993-02 average. This reflects the wetter months of July seen in the last 10-years compared with both the long-term average 64% and 1971-2000 average 67%. The beginning of the month was dry with only 2.4 mm in the first 15 days. The effect was seen in soil moisture values that were lowest of the year (41.0 litres m² x10 cm deep) since the dry spell in April (41.8 litres m² x10 cm deep). The end of the month was wetter with most (47.7 mm) of the total accumulated. The 24th with 12.7 mm was the wettest day with the 29th a close second with 10.4 mm. Dry days numbered 10 (-1.6) while there were 14 rain days (0.2 mm, or more). Wet days were 9 (-2.5) and those with 5 mm, or more, were 5 (-0.5). Overall the month ranked 25th driest since 1928, but up to the 15th it was the driest. Rainfall for the year now stands at 513 mm just below the 525 mm long-term average. Evaporation from the Piche evaporimeter was 51.1 ml ranking second to the 54.9 ml in 1999, but PE (potential evapotranspiration) with 50.8 mm was only half the 112.9 mm seen in the drier (26 mm) and sunnier 1999.
There were 3 days with thunder (+2.4) with storms on 17/18th and 29th. There was no hail seen in the month. It was foggy on 4 days but not at 09 GMT.
August was a dry month and with only 2.9 mm up to the 20th it could have been the driest August on record here. But the 21 - 23rd brought 4.6 mm and another 9.2 mm on the 29th, most the result of a thunderstorm, brought the total to 16.8 mm (23%). The long-term (19%) and 1971-2000 (21%) averages were on this occasion similar. Number of dry days were 14 (+3.3) but another 8 had only trace amounts. The number of rain days 8 (-6.7) and wet days 5 (-6.5) were well down on average. There was only 1 (-4.5) fall over 5 mm.
The month was warm too with the mean maximum 20.8C (+1.3) and mean minimum 13.1C (+0.9). On the 1970-2000 average these were +1.5 and +1.6 respectively. The mean maximum was warmest since 1977 (21.5) and ranks 6. The mean minimum ranks equal 3 and the highest minimum of 17.7C ranks 3 and both warmest since 1977. The mean 17.0C was (+1.1) and +1.6 on the 30-year average. There were 17 days with 20C, or more including the spell 1 - 9th. There were 4 days with 25C or more with the highest 31.7C on the 5th just before it clouded over. This was the 2nd highest recorded temperature in August, or any month, at this station. At RAF Valley Met Station it kept clear and 33.0C was recorded, its highest temperature on record, equalling that observed here on 2 August 1990.
; "Amount of water (litres) in 1 square metre of soil under grass to a depth of 10 cm: © 2003 D.Perkins."){kind=small}
Relative humidity values through the month were fairly high (mean 83%). Lowest recorded were on the 5th and 17th both with 53%. Evaporation measured by Piche was 51.3 ml or (46.6 mm calculated on area) and highest recorded in August. By lysimeter it was 51.4 mm most since 2000 but less than 1997 that saw 77.3 mm. Soil temperatures at 30 cm averaged 18.5C, equalling 1997, but less than in 1995 with a mean of 19.1C. Soil water fell throughout the month and by the 28th was 33.1 litres m² x10 cm deep. Vegetable crops needed irrigation nearly every day but most garden (except hydrangeas) and rockery plants did not. Grass growth slowed and began to look a bit yellow and the lysimeter tank green in comparison by the 28th. Unlike 1976 and 1995 deeper rooting trees on a good soil depth have not, so far, shown signs of wilting. Some leaves have been falling, mainly on beech trees exposed to south-westerly winds.
Thunder was hear on 3 days, the 5th, 11th and on the 29th. The latter a local storm was accompanied by 2 close cloud to ground flashes of lightning and heavy rain that included some small ice pellets.
A month of contrasts. The first half was warm and sunny with a cooler, wetter spell in the middle. The second was cooler and wetter with 2 very wet days that made up 55% of the total rainfall.
 "Number of days in September with maximum of 20C, or more."){kind=small}
The mean temperature was 14.1C (+0.3) but [+0.8] on the 1971-2000 average. This ranked 9th warmest since 1979. The mean maximum was 17.7C (+0.5) and [+0.7] while the mean minimum was 10.5C (+0.3) and [+0.8], ranking 8th and 9th respectively. The differences from the averages are a reflection the warmer temperatures of the past 10 years. The warmest days were on the 4th and 14th with 23.5C (+0.5) the same as last year. There were 9 days with 20C or more. Last year there were 8 this following 2 cool Septembers, but are short of the warmest in 1998 with 12 days. The coolest day was on the 27th with a maximum of 13.1C but the 23rd had only 13.7C. This followed the coldest night that had a minimum of 6.0C while above the grass it was 2.7C.
 "Click for rainfall anomalies in September at llansadwrn 1928-2003."){kind=small}
Total rainfall for the month was 159.7 mm (172%) and ranks the 8th wettest in records since 1928. It was the wettest September since 1999 (174.3 mm) and is in contrast to last year (23.0 mm). The wettest day on the 29th recorded 55.4 mm and becomes the wettest in September at this station. But a larger fall of 82.6 mm occurred in Llansadwrn on 19th September 1946. It is also the 2nd wettest day seen at this station (69.1 mm on 21st March 1981). There were, however, 9 dry days (-1.7). Rain days numbered 16 (+1.0) and wet days 12 (-0.4C) while days with 5 mm, or more, were 8 (+1.3). PE was 25.5 mm and evaporation from the Piche was 42.2 ml. The large rainfall meant that there was a water balance of 134.2 mm keeping the year well in surplus with 376 mm.
Valley reported 129.0 h of sunshine and was 84% of the 10-y average (91% of 30-y). Sunniest day was on the 13th (11.3h), 3 days were sunless and another 3 had less than 1h.
No thunder was heard in the month but small ice pellets fell on the 23rd.
Wettest at the beginning with some warmer sunny days in the middle. Turned colder and wetter again at the end
The coolest October since 1993 with the mean temperature of 9.7C 1.5C below average. The mean maximum 12.8C (-1.4) and mean minimum (-1.6) were both coolest since 1993. The warmest day was on the 11th having a maximum of 17.6C (-2.1) while the coldest on the 21st had only 6.8C (-3.5), the coldest day in October on 25-year record. The lowest minimum of 2.1C (-1.1) was on the 30th that also saw the lowest grass minimum -1.6C (-0.8). No airfrost was recorded but there were 3 days(+0.6) with ground frost. Small hail (ice pellets) were seen to fall on 6 days including the 21st that also had sleet in the evening. Thunder was heard on the 24th.
A total rainfall of 56.1 mm was only 48% of average and was close to both the long-term and 30-y averages. It was the driest October since 1997 (53.6 mm) and ranked 9th driest on record since 1928. Wettest day was the 5th with 11.4 mm. Rain days numbered 17 (-2.7) while there were 13 (-2.9) wet days. There were 10 completely dry days (+1.4) and only 3 (-5.3) days had 5 mm, or more.
Valley reported 118.2 h of sunshine close to the average of the last 10 years (115.4 h) but was 10% more than the 30-year average. Sunniest days were the 1st 9.2h, 2nd 9.8h (most), 17th & 18th both 9.6 h, and 23rd with 8.8 h. Only 2 days were sunless (14, 28) but another 9 days only saw 1 h, or less.
A warm month with the mean 8.9C (+0.8) but [+1.2] on the 1971-2000 average and ranking 4 on record at this station. It was warmer in 1994 that had a mean of 10.1C. The mean maximum 11.8C (+1.2) was 1.8C warmer than the 30-y average. The daily mean of 15.0C on the 5th, the highest in November on record, beat the previous 16.6C in 1997. There were 3 warm sunny days 5 - 7th, the highest maximum 18.7C on the 5th (+3.6) was the highest on record in November beating the previous high of 17.3C in 1997 by 1.4C. The 7th had 18.7C while the 6th had 17.5C. The mean minimum 6.0C was only (+0.4) or [+1.2] did not beat any records and ranks 4th highest with 7.9C seen in 1994. There were no airfrosts, the lowest minimum 1.6C (+0.7) was on the 27th. On the grass it was cooler with 9 frosts (+0.2) the coldest -2.5C on the 23rd and 24th.
Rainfall 126.4 was close to the average (95%) and of median rank. It was not as wet as 2002 (184.6 mm) but wetter than 2001 (107.7 mm). There were 3 wet days 18.5 mm on the 1st, 27.7 mm on the 19th (wettest day) and 22.0 mm on the 25th. Days of 5 mm or more numbered 8 (-0.9) and of 1.0 mm or more 18 (+0.9). There were 6 (+1.1) dry days, however, and days 0.2 mm, or more, were less than average with 19 (-3.2). While there were 29.6 mm evaporated from the Piche tube the lysimeter recorded a negative value (-0.5 mm). This often happens during the winter months when deposition of dew occurs.
Sunshine at RAF Valley was 68.8 h (+8.8). Sunniest day was on the 7th with 6.8 h with the 5 - 6th, 12th and 27th all having 5 h or more. The were 8 sunless days with another 3 almost, having 0.2 h, or less.
No thunder was heard but there were 5 falls of hail (+0.8). The 16th, 26th & 27th saw ice pellets. On the 2nd there was a fall 10 mm diameter hail with agglomerations of up to 15 mm diameter, these composed of pieces about 5 mm. More 5 mm hail fell after midnight so 2 days recorded large hail on this occasion.
Rainfall of 136.5 mm was 108% of average but 120% of the long-term average. There were 4 wet spells with 3 spells of dry days each with 3 days, or more, that were often sunny as well. The number of dry days were 10 and were 4 more than average. Number of rain days (0.2 mm or more) were 19 (-2.5) and wet days (1.0 mm or more) 14 (-3.0). Even days with 5 mm, or more, were less than normal with 7 (-2.4). The wetness was due to heavy rain on the 12th (26.2 mm), 25/26th 51.4 mm and 31st (17.0 mm). The 94.6 mm of these 4 days comprised 70% of the total. The wettest day was the 25th with 32.4 mm (16.8 h duration). Evaporation was the lowest of the year with the Piche evaporimeter recording only 21.6 ml while the lysimeter shows it's largest negative value with -6.1 mm. As evaporation by this method is a net calculation; it involves measured rainfall and is largely because dew (and frost) together with small amounts of precipitation (fog and drizzle) are not adequately recorded by the raingauge.
A warmer than average month with the mean 5.9C (+0.3) and [+0.4] on the 30-y average. The mean maximum 8.3C and mean minimum 3.4C were similarly just above average. The highest maximum 11.7C (-1.2) was on the 12th with 3 others reaching 10C or more. Lowest maximum of 2.5C (-0.2) was on the 30th. The highest minimum 8.7C (-0.4) was on the 26th while the lowest -2.5C (-0.2) was on the 8th. This day also saw the lowest grass minimum 9.2C (-2.7) but the 30th was cold too with minimum -1.8C and grass minimum -5.6C.
Hail (all types) fell on 6 days (+0.7), most were ice pellets but large hail (7 mm diameter) was seen on the 26th. Snow pellets were recorded on the 22nd and 28th while snowflakes were seen on the 22nd. Days with snow were below average (-2.1) and there was no lying snow (-1.5). Thunder was not heard in the month.
At RAF Valley sunshine totalled 55.8h (101%) but 114% of the 30-year average ranking it the 17th sunniest on record. Sunniest days was were on the 5th and 7th with 6.2h each. But there were 11 sunless days in a month that also had another 4 with 1h, or less. This was made up for by the 6 days that had 5h, or more
The year ranks as one of the warmest 3 on record here since 1979. The annual mean of 10.7C (+0.7) [+0.8] equalled that of 1990 and 1997. The mean maximum of 14.0C (+0.7) [+0.6] was warmest since 1997 (14.0) and is ranked 4th warmest. The mean minimum of 7.3C (+0.3), even warmer  "Annual mean temperature histogram."){kind=small}
 "Annual mean temperature anomaly."){kind=small}
than the 1971 - 2000 average [+0.9], ranks 5th warmest. The histogram shows the mean plotted over the 25-years of station records. Fitted to a linear regression the temperature increases over the period by about 1C an indication the warming that has taken place in recent years. The other graphic shows the mean anomaly (differences from the 1979 -2003 mean) over the same period. Since 1989 there have been 8 years with an anomaly of 0.5C, or more.
The warmest month was August with a mean of 17.0C (+1.1) while the coldest was January with a mean of 5.2C (-0.3). August saw the highest mean maximum of 20.8C and January the coldest with 7.3C. The mean minimum was highest 13.4C in July and coldest 1.8C in February. Warmest day was on August 5th with a maximum of 31.7C while the lowest maximum of 1.7C was on the 7th January. The lowest minimum of -3.1 was recorded on February 15th while the highest 18.9C was on July 16th. There were 21 days (+3.3) on which airfrost occurred and were the most since 1996 (40) apart from 2001 (28). The year was airfrost-free from 11th April to 7 December some 241 days. The lowest grass minimum of -9.2C did not occur until 8th December. Overall there were 82 days on which there was ground frost (24-h 09-09 GMT). Apart from the 89 days seen in 2001 they were the most seen since the 90 days in 1996. It was ground frost-free from 4 May to 23rd October, some 173 days.
Total rainfall for the year was 1008.5 mm (95%) [102%] and was drier than 2002 (1187.2 mm) but wetter than 2001 (866.0 mm). The year was 97% of the long-term average and ranks only 25th driest in records since 1929. But 5 months had 100 mm, or more. Wettest was September with 159.7 mm (172%) but May with 148.3 mm (229%) was not far behind. Other wet months were November with 126.4 mm and December with 136.5 mm but these can be expected to be wet and is reflected in their averages, (95%) and (108%) respectively. Driest month was August with only 16.8 mm (23%). Other dry months were February with 45.5 mm (43%), March 51.3 mm (70%) and October 56.1 mm (48%). The number of dry days 121 was (11) more than average while days with rain were all below average. Rain days (0.2 mm, or more) numbered 182 (-26) and wet days (1.0 mm, or more) 136 (-24). Days with 5 mm, or more, were (15) below average. The wettest day was on September 29th with 55.4 mm.
Days with sleet or snow were only 6 and (8.2) below average. There was no lying snow recorded at 09 GMT this being (3.5) below average. Days with thunder were 7 and (1.0) below average. But days with falls of hail 34 were (5.9) above average and ranked 4th highest since 1979. Most 31 were <5 mm diameter but there were 3 days that had hailstones of 5 mm, or more.
Complete weather diary for 2003.
View the complete daily observations for 2003.
Llansadwrn (Anglesey): Monthly weather data for 2003.
(~ Based on the 1993-02 average)
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Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
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Air temperatures (C)
Mean max 7.3 9.0 12.3 14.5 15.0 18.8 19.9 20.8 17.7 12.8 11.8 8.3 14.0
Mean min 3.1 1.8 3.9 6.0 8.2 11.2 13.4 13.1 10.5 6.5 6.0 3.4 7.3
Mean 5.2 5.4 8.1 10.3 11.6 15.0 16.7 17.0 14.1 9.7 8.9 5.8 10.7
Anomaly~ -0.3 -0.4 +1.1 +1.6 0.0 +1.5 +1.2 +1.1 +0.3 -1.5 +1.2 +0.3 +0.5
High max 12.1 14.9 17.4 25.3 24.8 23.9 31.2 31.7 23.5 17.6 18.7 11.7 31.7
Date 26 26 28 16 30 16 14 5 4,14 11 5 12 5 Aug
Low max 1.7 4.6 8.1 8.4 9.5 14.1 14.9 15.0 13.1 6.8 6.5 2.5 1.7
Date 7 14 12 10 2 4 4 31 27 21 26 30 7 Jan
High min 8.8 7.7 8.0 10.3 14.0 14.4 18.9 17.7 15.0 11.7 11.5 8.7 18.9
Date 27 26 9-11 15 30 27 16 9 18 9 18,19 26 16 Jul
Low min -2.9 -3.1 -1.5 -1.3 3.3 8.5 9.2 7.5 6 2.1 1.6 -2.5 -3.1
Date 8 15 14 10 10 20 1 31 23 30 27 8 15 Feb
Grass min -7.3 -9.0 -7.0 -6.0 -0.4 5.3 6.8 5.0 2.7 -1.6 -2.5 -9.2 -9.2
Date 5 15,18 14 10 3 20 12 31 23 30 23,24 8 8 Dec
Atmospheric moisture means
RH (%) 88 83 80 78 83 80 84 83 84 86 92 90 84
Dew point (C) 3.1 1.5 4.4 6.3 8.6 11.8 13.6 14.0 11.4 6.8 6.8 4.3 7.7
Soil temperatures (C)
5 cm 4.1 3.2 6.1 10.2 13.0 17.3 18.2 18.0 14.2 9.2 7.3 4.9 10.5
10 cm 4.5 3.7 6.4 9.7 12.1 16.1 17.4 17.5 14.0 9.7 7.7 5.3 10.3
20 cm 5.1 4.5 7.2 10.3 12.3 16.2 17.7 18.1 14.7 11.0 8.6 6.0 11.0
30 cm 5.4 4.9 7.7 11.0 13.0 16.8 18.1 18.5 15.6 11.8 9.2 6.5 11.5
50 cm 6.1 5.6 7.9 10.9 12.8 16.3 17.9 18.3 16.0 12.7 9.9 7.4 11.8
100 cm 7.1 6.6 7.9 10.4 12.0 14.9 16.5 17.3 15.8 13.3 10.8 8.6 11.8
Rainfall (mm)
Rain tot 82.2 45.5 51.3 66.6 148.3 69.0 50.1 16.8 159.7 56.1 126.4 136.5 1008.5
Rain % ave~ 82 43 70 89 229 95 89 23 172 48 95 108 95
Days, dry 8 12 16 16 5 10 10 14 9 10 1 10 121
Days >=0.2 18 13 10 12 22 14 14 8 16 17 19 19 182
Days >=1.0 14 10 5 10 15 11 9 5 12 13 18 14 136
Days >=5.0 6 2 3 4 9 5 5 1 8 3 8 7 61
Max fall 15.6 23.5 15.8 17.8 27.8 20.5 12.7 9.2 55.4 11.4 27.7 32.4 55.4
Date 24 8 31 29 21 30 24 29 29 5 19 25 29 Sep
Evaporation
Piche (mls) 29.6 33.9 47.4 53.0 45.1 49.5 51.1 51.3 42.2 37.1 29.6 21.6 491.4
Lysimeter (mm) -1.4 -0.8 22.9 50.1 50.7 64.5 50.8 51.4 25.5 10.3 -0.5 -6.1 317.4
Weather (days)
Air frost 6 9 1 1 0 0 0 0 0 0 0 4 21
Ground fr 10 21 16 8 1 0 0 0 0 3 9 14 82
Sl/snow 2 2 0 0 0 0 0 0 0 1 0 1 6
Sn lying 0 0 0 0 0 0 0 0 0 0 0 0 0
Thunder 0 0 0 0 0 0 3 3 0 1 0 0 7
Hail <5 mm 5 4 1 3 2 0 0 1 1 6 3 5 31
Hail >=5 mm 0 0 0 0 0 0 0 0 0 0 2 1 3
Fog at 09h 0 0 2 0 0 0 0 1 0 0 0 1 4
Gales 2 0 2 0 0 0 0 0 0 0 2 1 7
Wind direction at 09h (days)
N 3 1 4 3 0 1 3 7 3 3 0 6 34
NE 5 4 5 7 1 4 4 7 0 6 1 5 49
E 3 1 2 4 1 1 1 2 0 7 1 4 27
SE 2 7 2 4 1 1 0 3 1 3 5 5 34
S 5 6 6 4 7 11 12 4 9 1 5 3 73
SW 5 2 9 8 11 6 8 4 6 2 6 3 70
W 4 3 1 0 4 2 1 3 7 4 5 3 37
NW 4 3 1 0 6 3 1 0 2 2 4 2 28
Calm 0 1 1 0 0 1 1 1 2 3 3 0 13
Autographic records of rainfall and frost duration (h)
Rain 65.4 35.8 32.1 42.8 100.1 56.7 51.3 14.2 103.2 65.2 93.5 107.5 767.8
Frost 64.8 77.8 10.6 6.5 0.0 0.0 0.0 0.0 0.0 0.0 0.0 37.8 197.5
Cloud cover at 09 GMT
Mean (%) 73 59 59 63 80 79 81 69 66 65 69 81 70
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I am grateful to Robert Jones, Admin. Officer at the Met Office RAF Valley, for providing data quoted from Valley.
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These pages are designed and written by Donald Perkins © 1998 - 2003 Document dated 2 April 2003 http://www.llansadwrn-wx.co.uk
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