|
Above average rainfall and below average temperatures A wet month carrying on from the record breaking wet 2020. The 180.6 mm of rainfall this month (169%) & [175%] of the new averages, even wetter than last, largest since 2008, ranking 7th in Llansadwrn records since 1928. The largest fall was on the 18th having 31.5 mm. There were 9 falls (+1.4) of 5 mm, or more; and 15 (-2.0) wet days. Rain days were 24 (+1.3); day days 7 (-1.3); and just one, he 31st, had no precipitation (-2.8) of average. Rainfall duration totalled 169 wet hours. Rainfall at Gorwel Heights totalled 205 .0 mm (223%) & [230%] of averages, wettest on record since 2011. The wettest day was on the 20th with 34.2 mm, 29.4 mm fell on the 18h and 28.6 mm on the 19th, the three days totalling 92.2 mm 45% of the monthly total. Days with 5 mm, or more, were 11; wet days were 17; rain days 22; and dry days 9. Rainfall duration totalled 173 wet hours. It was the coldest January since 2010. The mean temperature 4.1C (-1.4) & [-1.3] of the new averages, lowest since 2010 and ranking 6th in station records since 1979. The mean maximum 6.4C (-1.6) & [-1.5] ranked 5th in station records. The highest maximum 10.0C on the 19th (-1.9) equal lowest (2011) since 2010, the lowest 2.7C (-0.9) on the 8th lowest since 2013. The mean minimum 1.8C (-1.3) & [-1.1] equal lowest (2011) since 2010 ranked 12th. The lowest minimum was -2.2C on the 9th and lowest since 2014 (-2.8). There were 8 air frosts, most since 2013 (10), with 46.5h of frost. There were 21 ground frosts (+3.9) most since 2015 (25) with the lowest -9.2C (-2.9) on the 7th lowest since 2009 (-9.7C). The mean temperature at Gorwel Heights was 4.8C January lowest station record (-1.5) & [-1.4]. The mean maximum 6.6C was a January low station record with the highest 12.2C on the 28th second lowest on record 2019 (11.4C) The lowest maximum 2.3C on the 8th was fourth lowest (0.5C in 2013). The mean minimum 2.9C was lowest on record, the lowest -0.8C on the 9th was third lowest. There were 3 days of air frost but only 7.2h fell below freezing. The wintry month in Llansadwrn had 12 days (+5.5) of small hail, most since 2015. Sleet or snow fell on 6 days equal 2019, most since 2013. There were no days (-0.6) with snow lying at 0900 GMT, least since 2019 (2), there were 10 in 2010.
February 2021Above average temperatures, rainfall and sunshineA month of contrasts the beginning cold and wintry the end milder, wet and windy The mean temperature in the first half of the month 4.2C was below average (-1.7) & [-1.4], but by the end with a spell of very mild weather ended on 6.1C (+0.2) & [+0.5] of averages, lowest since 2018, but ranked 16th highest in station records. The mean maximum was 8.6C with the highest maximum 12.5C on the 20th and the lowest 1.7C on the 9th -2.6C based on the decadal average. The mean minimum was 3.6C with the highest 9.1C on the 20th and the lowest -2.1C on the 11th. There were 6 days of air frost of 53.3h duration. There were 12 days with a ground frost (-3.0), the lowest -7.3C on the 11th (-1.3) of average. At Gorwel Heights the mean temperature was 6.8C [(+0.6)] of averages, equal highest with 2014 since 2011. The mean maximum was 9.3C highest since 2019 (12.0C), the highest maximum was 14.3C on the 23rd second only to Rhyl's 15.0C, it was only 11.2C in Llansadwrn. The mean minimum was 4.2C lowest since 2018, the lowest minimum -2.3C on the 13th, frost duration was 71.5h, there were six air frosts in a spell from the 9-14th. It was a wet month in Llansadwrn where rainfall totalled 146.6 mm (143%) & [182%] of averages, lowest since 2019, ranking the 8th wettest February in Llansadwrn records since 1928 The wettest day was on the 23rd when 50.6 mm fell over 23h duration, the second highest February daily total in station records since 1979 only beaten by the 55.3 mm recorded in 2020 when the months total reached a record 250.6 mm. There were 3 days (-2.0) with no precipitation, 11 (+2.4) dry days; 17 (-2.7) rain days; 15 (+1.8) wet days; and 9 (+2.8) had 5 mm, or more. It was drier at Gorwel Heights, the total rainfall 95.8 mm, lowest since 2019, (113%) & [128%] of averages. The wettest day was on the 23rd with 18.4 mm over 21h duration. Rainfall duration during the month was 104h. Dry days were 13; rain days 15; wet days 12; and 8 days had 5 mm, or more. A very windy month at Gorwel Heights with a mean wind speed of 8.8 mph, the highest 25.4 mph on the 12th and 23.3 mph on the 23rd. On 10 days high gusts of more that 40 mph were recorded, highest recorded were 57 mph on the 18th; 58 mph on the 19th; 63 mph on the 20th and 64 mph when significant structural damage occurred in the village of Llanfairfechan. In Llansadwrn snow fell on 2 days and small hail on 7 days. Sunshine at RAF Valley totalled 92.8h, sunniest since 2019 ranking the 20th sunniest February on the Anglesey record back to 1931. The sunniest day was on the 28th with 10.1h duration, there were 7 sunless days. Winter 2020/21Second wettest winter on record in Llansadwrn. Temperatures below the station averages.
March 2021Temperatures and rainfall above average, a little duller than averageWet and wintry at times, above average temperatures at the end of the month Another wet month with 124.7 mm bringing the total so far this year to 451.9 mm, but 64.7 mm below last year's total. Wettest in March since 2019 and (151%) & [159%] of averages. The wettest day was on the 14th with 30.0 mm while 23.8 mm fell the next day resulting in standing water on garden and fields. Despite this there were 8 days (+0.6) with no precipitation and 13 dry days (+0.1). Rain days were 18 (-0.1); wet days 11 (-3.5); and 6 days (-2.4) had 5 mm, or more. It was drier in Llanfairfechan at Gorwel heights with 90.0 mm (103%) & [109%] of averages. The wettest day was on the 9th having 13.4 mm with 12.6 mm falling on the next day. The 27th had 12.0 mm and the 28th 11.2 mm. There were 15 dry days; 16 rain days; 13 wet days; and 8 had 5 mm, or more. Rainfall duration (wet hours) was 92h at Gorwel Heights and 99h in Llansadwrn. It was wintry at times with sleet falling on the 11th and 26th. Hail fell on 3 days (-2.3) of average. A windy month with gales in the area on 5 days. Temperatures were a little above normal with the mean 7.4C (+0.5) & [+0.4] of averages, highest since 2019 ranking 15th since 1979. The mean maximum was 10.3C with the highest maxima 18.6C on the 30th and 16.8C on the 31st the only two >15C. There were 15 days <10C the lowest maximum 5.6C on the 4th. The mean minimum was 4.4C (+0.8) & [+0.7] of averages. There were 2 air frosts this month the lowest -1.0C on the 6th the other -0.6C the previous day. There were 7 ground frosts, significantly (-8.0) of average, the lowest -6.4C on the 6th was (-1.7). A little warmer in Llanfairfechan at Gorwel Heights with the mean 7.9C [(+0.4)] highest since 2014. The highest maxima were 17.7C on the 30th highest since 2014 and 16.1C on the 31st. The mean minimum was 5.3C equal highest (2019) since 2017. There were no air frosts the lowest 0.8C on the 7th. Sunshine at RAF Valley totalled 114.4h (88%) & [95%] of averages. The sunniest day was on the 1st of the month with 10.3h and there were 7 sunless days.
April 2021Sunniest on record. Very dry, but temperatures lower than averagesWintry at the beginning, very dry in the latter half A very dry month with 16.7 mm of rainfall (31%) & [25%] of averages, the 6th lowest on record in Llansadwrn since records began in 1928. The lowest 6.7 mm in 1980 and 11.7 in 1984 mm are held by this station; 11.9 mm was recorded at Treffos in 1938, 13.2 mm in 1957 and 15.0 mm in 1974. There was no precipitation on 16 days (+4.4) and there were 19 dry days (+4.8). Rain days were 11 (-4.8); wet days 7 (-4.3). The wettest day with 3.6 mm fell on the 30th. At Gorwel Heights 16.6 mm fell in the month (22%) & [26%] of averages, the driest on record since 2011. There were 19 dry days; 11 rain days; 8 wet days; and none exceeded 5 mm. The wettest day on the 11th had 4.8 mm. Rainfall duration was only 25 h and at Llansadwrn 34 h. The month had lower than average temperatures with frequent cool air from Arctic regions. Sleet or snow fell on 5 days (+4.3), the most since 1998, and small hail on 5 days (+2.2). I have not recorded any lying snow in April. The mean temperature 7.7C (-1.6) & [-1.4] of averages was lowest since 2013 ranking 8th in station records since 1979. The mean minimum 3.4C (-2.2) & [-2.0] of averages ranked 3rd lowest in records. The lowest minimum was -0.1C on the 11th, equal lowest with 2015 since 2013 that had -1.1C. There were 16 ground frosts (+9.0) the hardest -4.3C on the 11th, a record number at this station in April, previous highest 14 in 2013. The warmest day was on the 23rd having 19.8C in the afternoon with a low RH of 24% at 1632 GMT. At Gorwel Heights the mean temperature was 7.8C (-2.1) & [-1.8] of averages, second lowest on record at this station (2012 had 7.7C). The mean maximum was 11.0C with the highest maximum 18.6C on the 23rd. The mean minimum was 4.6C, lowest 0.7C on the 11th so no air frost here. It was a record sunny April at RAF Valley by a mile. The provisional 251 h of sunshine (one missing record on 28th estimated as 3.1h) most on the Anglesey record since 1931. The previous sunniest April was in 2015 having 232.7 h. The sunniest day was on the 22nd with 13.1h and there were no sunless days.
May 2021Wet with temperatures below averagesWintry at the beginning with a hint of summer at the end Another wet month bringing the total rainfall accumulated in the year so far 608.9 mm, half the annual averages, to the most in Llansadwrn since records began in 1928 exceeding last year's record amount. Rainfall in May was 140.3 mm (208%) & [207%] of averages, ranking 3rd wettest on record only exceeded by 2015 141.3 mm and 2003 148.3 mm. The six wettest Mays in Treffos and Gadlys in Llansadwrn, with only a few millimetres between them, are shown in the graphic. Four of these large falls occurred in the last 40 years and two in the previous 60 years, more frequent falls are an indication of the climate changing The wettest day was on the 20th having 35.2 mm, six days (+1.4) exceeded 5 mm and 19 were wet days (+8.8) with 1 mm, or more. There were however five days (-7.2) with no precipitation; 7 (-9.0) were dry <0.2 mm; and there were 24 (+9) rain days, those defined as having 0.2 mm, or more. Rainfall duration was 129 wet hours. It was wet too in Llanfairfechan, at Gorwel Heights rainfall was 154.8 mm (2025) & [201%] of averages. The wettest day was on the 20th when 40.2 mm fell. There were 8 dry days; 23 rain days; 17 wet days; and 7 days had 5 mm, or more. Rainfall duration was 134 wet hours. May followed on from April with lower than average temperatures making it a colder spring than in recent years. The mean temperature 10.6C [(-1.2)] was lowest since 2015 ranked 6 in station records since 1979. The mean maximum 14.4C (-1.1) & [-1.2] again lowest since 2015 ranked 7. The highest maximum had to wait until the 30th for 21.9C (-0.3) while the lowest was 10.9C (+0.3) on the 3rd. The mean minimum 6.7C [(-1.2)] ranked 6, the lowest 0.7C (-2.7) was on the 6th. There were 5 ground frosts (+3.6) with the lowest -2.7C (-1.7) on the 7th. The mean temperature at Gorwel Heights 10.8C (-0.9) & [-1.7] of averages with 2013 and 2015 lowest in station records since 2011. The mean maximum 14.1C was lowest since 2015 rank 2 with the highest maximum 23.1C on the 30th. The mean minimum 7.5C was lowest in station records in May, the lowest minimum 2.2C was on the 6th again lowest in station records since 2011. Spring 2021With 281.7 mm rainfall it was the seventh wettest winter on record in Llansadwrn, last year with 122.7 mm was the fourth driest on record. The wettest spring was in 1947 having 352.0 mm the driest 1990 with 80.2 mm. Temperatures were below the station averages with the mean lowest since 2015.
June 2021Drier and warmer than average and fairly sunnySome nice summer days with awful ones in between Rainfall was less than normal the 44.9 mm (54%) & [61%] of averages least since 2018 and ranked 25th lowest in Llansadwrn records since 1918. Despite the lower than average figures the total for the year so far 653.8 mm is the largest recorded in Llansadwrn to this date. The most rain 17.5 mm fell on the 25th, a really awful day that was also the dullest, with rainfall duration 11 h. There were, however, 16 days (+5.2) with no precipitation and 21 (+6.5) were recorded as dry (<0.2 mm). Rain days were 9 (-6.5); wet days 6 (-5.9); and 4 (-1.2) had 5 mm, or more. Rainfall duration (wet hours) was 57h. Rainfall at Gorwel Heights was 44.2 mm (56%) & [62%] of averages. Here the wettest day was also on the 25th with 22.4 mm. Dry days were 24; rain days 6; wet days 6; and 3 had 5 mm, or more. Rainfall duration (wet hours) was 51h. The mean temperature in Llansadwrn was 14.7C (+0.5) & [+0.7] equal highest since 2018 ranking 13th in station records since 1979. The mean maximum was 18.5C ranking 11th, highest since 2019, the highest 24.2C was on the 1st and the lowest 13.2C on the truly awful day of the 25th. The mean minimum was 11.0C lowest since 2015 ranking 9th highest while the highest 13.7C was on the 2nd and the lowest 7.9C on the 23rd, this lowest since 2015. The lowest grass minimum 4.0C (+0.9) was on the 5th. A Gorwel Heights the mean temperature was 15.9C (+1.1) & [+1.0] of averages with the highest 20.1C was on the 2nd and lowest 11.7C on the awful 25th. The mean maximum was 19.6C with the highest 25.3C on the 13th. Twelve days had >20C with 24.3C on the 1st and 24.4C on the 2nd. The mean minimum was 12.2C with the highest 15.8C on the 2nd and the lowest 9.5C on the 4th. Sunshine at RAF Valley was 201.3h most since 2019 and ranking 29th on the Anglesey record since 1931. The sunniest day was on the 4th with 15.7h and there were 6 sunless days. 
Monthly data 2021
Llanfairfechan, Gorwel Heights observations
AcknowledgementsThe Met Office at RAF Valley kindly supplied observational data from 1942 to 2011. Current data (provisional) are gathered from SYNOP reports and METAR, any missing observations are initially derived from nearby stations to complete the record, up to date figures are later gathered from the Met Office website. I am grateful Ivor McLean former Met Officer at RAF Valley for early Holyhead sunshine and various other observations; David Lee for use of his observations from Gorddinog; and Gordon Perkins (BlueTractorSoftware) for observations at Gorwel Heights and providing additional observations.
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 "May rainfalls at Llansadwrn since 1928.")