Llansadwrn (Anglesey) Weather:
Monthly and Annual
Summary for 2016

• Llansadwrn data table
• Gorwel Heights data table

• January
• February
• Winter
• March
• April
• May
  • Spring
• June
• July
• August
  • Summer
• September
• October
• November
  • Autumn
• December
  
  
• Acknowledgements

• Llansadwrn data table
• Gorwel Heights data table

   

  Note: Values in (.) refer to the 10-y 2005-2014 average; [.] refer to the 30-y 1981-2010 climatological average while {.} refer to the station's different LTA (long-term averages). All data are subject to verification and amendment. Javascript must be enabled to see the pop-up graphics.

  

January 2016

Mild, wet and windy at times

The middle of the month was more settled, quieter and cooler.

A generally mild month with a mean temperature of 6.5C (+1.3) & [+1.4] of averages, highest since 2008 and 12th highest since before 1979. The mean maximum was 9.0C [(+1.4)} that was highest since 2007 rank 7th since before 1979. The highest maximum was 14.2C (+2.8) on the 24th was 3rd highest in January on record, behind the record 16.5C on 10 January 1998 and 14.6C on 11 January 1998. The lowest maximum was 5.3C (+2.6) on the 14th 6th highest on record in January; 5.6C was recorded in both 1988 and 1989.

The mean minimum was 3.9C (+1.2) & [+1.3] of averages, highest since 2008 rank 8th. The highest 11.0C (+2.4) was on the 25th, 2nd highest on record in January lower than the 12.2C recorded on 11 January 1998. The lowest minimum was 0.1C (+2.3) on the 21st, this was only the 3rd January here without air frost (0.1C in 2000, 0.7C in 2005). There were 14 ground frosts (-3.0), lowest since 2008.

At Gorwel Heights the mean temperature was 7.3C [+1.1] of average, the highest daily mean 14.3C was on the 25th and the lowest 3.4C on the 15th. The highest maximums were 16.8C on the 24th, 15.7C on the 21st and 15.2C on the 25th. The lowest maxima were 5.3C on the 14th and 5.4C on the 15th. The mean minimum was 4.9C, the highest was 13.4C on the 25th and the lowest 1.4C on the 15th, again no air frost was recorded.

A moderately wet January with 159.2 mm recorded in Llansadwrn (149%) & [156%] of averages, largest since 2008 and ranking 12th in records back to 1928. There were 6 falls of 10 mm, or more, the largest falls 22.2 mm on the 7th and 21.6 mm on the 26th. There were 9 (+0.7) falls of 5 mm, or more; 22 (+5.2) wet days; 28 (+7.3) rain days; 3 (-7.3) dry days and just 2 (-4.1) days with no precipitation. Rain duration (wet hours) numbered 178 and the average rate of fall was 0.9 mm per hour.

Rainfall at Gorwel Heights was 166.2 mm [147%]. Largest falls were 23.2 mm on the 7th and 18.4 mm on the 6th. Rainfall duration (wet hours) numbered 170 and the average rate of fall 1.0 mm per hour. . ...

Above average rainfall with near average temperatures and sunshine

Some very wet days and a scattering of wintry weather, but no lying snow

Precipitation, mostly rain, was 107.7 mm (158%) & [137%] of averages, highest since 2014 ranking 23 since 1928. The largest fall was 23.2 mm on the 29th with 15.5 mm on the 6th; 11.6 mm on the 16th; and 14.4 mm on the 20th. There were 7 days with no precipiation and 9 dry days (-2.3). Rain days were 15 (+3.6) and wet days 15 (+3.8) with 6 days having 5 mm (+1.6), or more. Rainfall duration was 119 wet hours with an average rate of fall of 0.9 mm/h. At Gorwel Heights rainfall was 85.0 mm [109%] with 108 h duration and an average 0.8 mm/h rate of fall. There were 11 dry days; 18 rain days; 13 wet days and there were 6 with 5 mm, or more.

Temperatures were close to the averages. The mean temperature in Llansadwrn was 5.4C, highest since 2014 and (-0.1) & [+0.1] of averages. The highest maximum was 11.1C on the 1st of the month and the lowest 4.6C on the 25th. The highest minimum was 7.7C on the 5th while the lowest was -1.2C on the 16th. There were just 4 days aith air frost and 18.3h frost duration. There were 20 days of ground frost (+5.1) with the lowest grass minimum -7.2C on the 24th and the next lowest 6.8C on the 18th. At Gorwel Heights the mean temperature was 5.9C spot on the 30-y average. The highest maximum was 13.4C on the 21st and the lowest 4.7C on the 17th. The highest minimum was 8.6C on the 5th with the lowest 0.2C on the 16th so there were no air frosts recorded.

Winter 2015/16

Warmest and wettest winter on record

The winter mean temperature was 7.0C (+1.6) and [+1.7] of averages, the highest since before 1979 in station records and before 1941/42 on the Llansadwrn comparative series back to 1941/42. Closest to this value on station records were 1997/98 with a mean of 6.9C and 2006/07 with a mean of 6.8C, then 6.6C in 1942/43 (graphic left). This winter's high mean temperature was due largely to the exceptionally high temperatures recorded in December 2015. Winter rainfall was remarkable with 682.7 mm [+381.7], exceeding the previously wettest 1994/95 that had 510.3 mm [+209.3], nearly twice the previous 30-y anomaly (graphic right). The large winter rainfall was due largely to the exceptional rainfall in December 2015 totalling 415.8 mm, the largest of any month on record in Llansadwrn since 1928.

March 2016

A fairly dry month with close to average sunshine, but below average temperatures

Rainfall in Llansadwrn was 56.6 mm, lowest since 2012 and (79%) & [66%] of averages. The largest fall 16.6 mm was on the 26th. There were 9 (+0.4) days with no precipitation and 15 (-0.1) dry days. Rain days totalled 16 (0.1) and wet days 11 (-0.9). There were 3 (-1.9) days that had 5 mm, or more. At Gorwel Heights rainfall was 65.2 mm [75%] of average. The largest fall was 19.0 mm on the 26th. Dry days were 16, rain days 11 and there were 4 days having 5 mm, or more. Rainfall duration was 80 wet hours in Llansadwrn and 86 wet hours at Gorwel Heights.

Llansadwrn mean temperature was 6.3C lowest since 2013 ranking 11 since 1979. The highest maximum was 13.8C on the 13th and the lowest 4.9C on the 6th. The highest minimum was 7.6C on the 13th while the lowest was 0.1C on the 4th. Lowest grass minimum was -4.5C on the 17th and there were 15 (+1.2) days of ground frost. The Gorwel Heights mean temperature was 7.0C (-0.4). The highest maximum was 13.8C on the 26th and the lowest 4.5C on the 6th. The highest minimum was 8.2C on the 26th and the lowest 1.2C on the 4th.

Thunder-hail. Sudden lightning and almost simultaneous overhead thunder on the 27th at 1545 GMT produced a bright white light and loud discharge inside the weather house knocking out the station's internet modem. The above ground electricity supply went off, but was soon restored. This was followed by another cloud to ground lightning strike seen to the east of the station, again the electricity supply was off for some seconds then restored, and a shower of ice pellets at a melting rate of 1.6 mm per hour in the 10 mins up to 1600 GMT (the AWS gauge heater was not on). This was followed at 1715 GMT was a shower of 8 to 11 mm hail (code 6) heavily indented the hail-pad and covered the ground with a melting rate of 5.6 mm per hour by 1720 GMT and 3.6 mm per hour by 1730 GMT. Several households reported damage of equipment and on the Monday morning the Beaumaris Post Office computers were still offline at 10 am due, the Postmaster said, to the electrical surge, and no financial transactions could be effected until later. The weather station AWS was back online later in the day using a back-up modem.

April 2016

Cool and wet with near average sunshine

A wet beginning with largest daily rainfall totals on the 1st with 15.8 mm and the 3rd with 14.6 mm. Total for the month was 78.8 mm (146%) & [124%] of averages. Largest in April since 2012 that had 100.1 mm ranking 28th since 1928. There were 9 (-2.8) days with no precipitation and 13 (-3.1) dry days. Rain days were 17 (+3.1) and wet days 15 (+5.8). There were 5 (+1.2) days that had 5 mm, or more. Rainfall duration was 107 wet hours.

Rainfall at Gorwel Heights was 80.6 mm [128%] of average with the wettest days having 14.2 mm on the 3rd and 14.0 mm on the 11th. There were 11 dry days, 19 rain days and 16 wet days. There were 5 days with 5 mm, or more. Rainfall duration was 108 wet hours.

The mean temperature in Llansadwrn was 7.9C (-1.5) & [-1.0] of averages, lowest since 2013 and 9th lowest at the station since 1979. The highest maximum was 16.7C (-2.0) on the 20th and the lowest minimum 0.3C on the 17th so no air frost. There were 11 (+3.3) days of ground frost with the coldest night on the 17th with -4.4C recorded. The temperature in the soil at 30 cm averaged 9.5C (-0.7).

Similar at Gorwel Heights. The mean maximum was 8.2C [-0.8] with the highest maximum 17.3C on the 20th and the lowest minimum 2.1C on the 29th.

May 2016

Sunny and drier and warmer than average

It was the driest May since 2013 after the wet 2014 and 2015. The 51.9 mm ranked 41 lowest in Llansadwrn since 1928 being (75%) & [95%] of averages. The wettest day with 11.4 mm was on the 19th. There were 16 days (+5.8) with no precipitation at all while there were 17 dry days (+3.3). Rain days were 13 (-4.3) there were 11 (-2.1) wet days, and 6 (+1.0) had 5 mm, or more. At Gorwel Heights 68.4 mm of rain fell [113%] of average. Here the wettest days were on the 28th with a fall of 18.2 mm and 10th with 15.2 mm. Dry days were 15; rain days 16; and wet days 11. Four days had 5 mm, or more. Rainfall durations (wet hours) were 64 h at Gorwel Heights and 76 h in Llansadwrn.

After 2 colder than average months based the 30-y average May temperatures were warmer. In Llansadwrn the mean 12.4 mean was C was (+0.9) & [+0.7] and highest since 2008 ranking 8th on station records since 1979. The highest mean was 17.6C on the 9th and the lowest 8.6C on the 14th, but this was followed by an 8.7C on the 25th. The highest maximum was 22.6C on the 8th and the lowest minimum 4.5C on the 15th. The lowest and only ground frost was -0.2C on the 3d. The highest maximum at Gorwel Heights was 23.4C on the 8th and the lowest minimum 5.6C on the 14th.

June 2016

Above average temperatures and rainfall, sunshine lower than decadal average

Rainfall totalled 108.2 mm (147%) & [160%] of averages, most since 2012 ranking 16 in Llansadwrn since 1929. Wettest days were the 19th with 32.4 mm and the 28th with 21.1 mm. There were 9 (-4.1) days without any precipitation; 15 (-0.8) dry days; 15 (+0.8) rain days; 13 (+2.0) wet days; and 7 (+2.5) days with 5 mm, or more. Rainfall duration (wet hours) was 78, it was humid at times the monthly 09 GMT average was 85%, the lowest relative humidity was 63% on the 3rd. Rainfall at Gorwel Heights was less with a total of 70.8 mm [108%] of average. Largest falls were 13.0 mm on the 16th; 11.0 mm on the 19th; and 9.2 mm on the 28th. There were 12 dry days; 18 Rain days; 13 wet days; and 7 days with 5 mm, or more. Wet hours totalled 74 and the average rainfall per hour was 1.0 mm. In Llansadwrn the average rainfall per hour was 1.4 mm.

The mean maximum in Llansadwrn was 18.3C with the highest 25.6C on the 6th and 25.5C on the 5th. The lowest maximum was 14.4C on the 29th. The mean minimum was 11.7C (+1.2) & [+1.6] of averages highest in station records since 1979, exceeding the previous highest 11.5C in 2006. The highest minimum was 15.0C on the 7th and the lowest 8.3C on the 3rd. The lowest grass minimum was 5.4C on the 23rd. The mean 15.0C, (+0.9) & [+1.1] of averages, was highest since 2010 ranking 6th since 1979. At Gorwel Heights the mean maximum was 18.4C with the highest 27.4C on the 5th and 24.0C on the 6th. The lowest maximum was 14.3C on the 17th. The mean minimum was 12.6C with the highest 15.4C on the 7th and lowest 10.2C on the 2nd. The mean temperature was 15.5C [+1.3] of average.

July 2016

Mostly dull and damp with low evapotranspiration and above average rainfall

There were 2 hot days the temperature reaching 25.5C (Gorwel Heights 26.4C) on the 18th and 31.6C on the 19th, highest since the all time record temperature of 34.9C in 2006 also on the 19th; there were 5 days of 20C, or more. It also reached 31.6C at Gorwel Heights and 31.7C at Gorddinog on the 19th the 3 stations reporting very similar values; Valley reported 32.2C and Mona 31.2C. The mean maximum in Llansadwrn was 18.8C [(-0.7)] of averages, but the highest maximum 31.6C was (+5.6). The mean minimum 12.5C was (+0.1) and [+0.5] of averages. The lowest minimum was 7.6C (-1.0) on the 2nd that also had the lowest grass minimum of 5.0C +(0.2). At Gorwel Heights the mean temperature 16.7C was [+0.5] of average.

Rainfall was 109.1 mm one of 22 Julys having 100 mm, or more, in Llansadwrn since 1928, ranking 18th. Since January 678.8 mm have fallen exceeding the 585.8 mm recorded by July in 2000, that turned out to be the wettest year on record in Llansadwrn. So far, every month has had a positive PWB (potential water balance) of 528.0 mm with PE (potential evapotranspiration) only 197.9 mm. The wettest day was on the 18th with 21.5 mm falling. Soil had remained moist throughout; on the 18th under grass it was 51% dm and increased to 56% dm on the 31st. There were, however, 8 days (-2.1) with no precipitation and 11 (-1.9) dry days. Rain days numbered 20 (+1.9) and there were 17 (+2.8) wet days. Days with 5 mm, or more, were 9 (+3.0). Rainfall duration (wet hours) were 123. It was somewhat drier at Gorwel Heights that had 84.4 mm [144%] of average; the wettest day was on the 19th having 19.2 mm. There were 10 dry days; 21 rain days; 17 wet days and 5 had 5 mm, or more; rainfall duration was 98 hours.

August 2016

Above average temperatures, rainfall and sunshine

It would have been a fairly dry month without the thunderstorm on the 27th that resulted in 65.0 mm of rain, over 9 hours duration, bringing the total to 133.0 mm (137%) & [153%] of averages. Most August rainfall since 2013 making it the 15th wettest since 1929. There were 12 (+5.5) days without any precipitation and 16 (+4.4) were dry. Rain days were 15 (-4.4) and wet days 11 (-2.5). Days having 5 mm, or more, numbered 7 (+1.7). Rainfall in Llanfairfechan at Gorddinog was 116.0 mm (52.1 mm on the 27th) while Gorwel Heights had 105.6 mm [125%] of average 49.8 mm on the 27th. Rainfall duration in Llansadwrn was 85 h, an average 1.6 mm falling per hour, and at Gorwel Heights 88 h, am average 1.2 mm falling per hour.

Temperatures were above average with the Llansadwrn mean 16.1C (+1.0) & [+0.5] of average highest since 2004 and ranking 8 in station records since 1979. The highest maximum was 26.0C (+3.7) on the 16th and there were 10 days that had 20C, or more, with a spell of 4 days 15 - 18th. The lowest maximum 15.8C (+1.6) was on the 10th. The mean minimum was 12.8C (+1.0) & [+0.5] of averages, highest since 2012. The highest minimum was 14.7C (-0.9) on the 28th and the lowest 9.2C (+1.0) was on the 9th that also had the lowest grass minimum 5.0C (+0.5). The mean temperature at Gorwel Heights was 17.0C [+0.9] with the highest maximum 24.9C on the 6th and lowest minimum 11.2C on the 10th. The highest maximum at Gorddinog was 25.5C on the 16th.

Summer 2016

Summer was rather wet with rainfall of 350.3 mm, largest since 2007, and ranked 9th in Llansadwrn since 1929. Summer was on the warm side with the mean temperature 15.6C [(+0.5)], highest since 2013, ranked 8th warmest at the station since 1979.

September 2016

Warmer and drier than average with near average sunshine. September hi min temperature record broken

A wet beginning then fairly dry with good sunny days

Mean temperatures were 1.5C above average in Llansadwrn and 2.0C at Gorwel Heights in Llanfairfechan. In Llansadwrn the mean, jointly second warmest year with 2014 in September records, was 15.3C (+1.4) & [+1.5] with a daily value of 20.3C on the 7th and the lowest 11.6C on the 30th. The warmest September being 2006 with a mean of 16.3C. Six days had maxima 20C, or more. At Gorwel Heights the mean was 16.4C [+2.0] with the highest 20.7C on the 6th and two other days exceeding 20C with 20.3C on the 7th and 20.2C on the 12th. The Llansadwrn mean maximum was 18.4C (+1.4) & [+1.1] of averages, third highest on record; the highest was 23.7C on the 14th. The lowest maximum was 14.3C on the 30th. The mean minimum 12.2C (+1.4) & [+1.9] of averages was second highest on record in September. The highest minimum, highest on record for September, was 17.2C (+2.5) on the 7th. The lowest minimum was 8.1C on the 22nd was third highest on record, while the lowest grass minimum was 5.1C on the 30th was second highest on record. At Gorwel Heights the mean maximum was 19.5C with the highest 26.3C recorded on the 14th; 11 days had maxima of 20C, or more. The mean minimum was 13.2C with the highest 17.3C on the 15th with the lowest 9.9C on the 18th.

Rainfall for the year in Llansadwrn had been running well above the total for the wettest year 2000 in June to August. The 84.3 mm (87%) and [88%] of averages, wettest since 2012, brought the total for the year to 896.2 mm some 185 mm ahead of the 2000 total to September. The largest fall was 15.4 mm on the 3rd. There were 7 (-2.7) days with no precipitation and 13 (+3.3) dry days. Rain days were 17 (+1.0; wet days 15 (+3.6) and 5 (-1.0) had 5 mm, or more. Gorwel Heights had 53.4 mm [55%] of average with the wettest day on the 3rd with 10.6 mm. Rainfall duration was 78 h while there were 95 h in Llansadwrn.

Sunshine at RAF Valley was 129.0 h (95%) & [101%] of averages; the sunniest day was on the 14th with 10.3h and there was just 1 sunless day. Last September sunshine was the most on record in September with 187.8 h, this year the month ranked only 34th in the Anglesey record since 1931.

October 2016

Driest October in 48-years, but temperatures were close to average

Warmest and sunniest at the beginning with one thundery downpour on the 16th

A dry month, the 37.9 mm of rainfall, [(29%)] of averages, was the lowest recorded in Llansadwrn since 1969 (32.3 mm at Gadlys Cottage and 33.5 mm at Treffos) and fifth lowest since 1928. The least on record in October was 8.6 mm recorded at Gadlys Cottage in 1946. The wettest days were on the 16th when thunder was heard with 14.4 mm, and a duration of 11 hours, the 1st had 7.1 mm over 10 hours duration, the only 2 days (-5.9) having 5 mm, or more. There were 13 (+5.9) days with no precipitation while there were 19 (+8.8) dry days. Rain days were 12 (-8.8) and wet days were 7 (-8.4). Gorwel Heights had 33.6 mm [27%] of average, the wettest day was on the 16th with 10.8 mm.

Temperatures ended the month close to the averages. The mean temperature in Llansadwrn was 11.1C (-0.4) & [+0.2] of averages, lowest since 2012. The mean maximum 13.8C (-0.4) & [-0.2] of averages also lowest since 2012, the highest maximum on the 3rd was 18.1C (-1.5). The mean minimum was 8.3C (-0.4) & [+0.6] highest since 2014, lowest was 5.5C (+_1.6) on the 23rd that also had the lowest grass minimum of 1.8C. The earth temperature at 30 cm averaged 12.7C spot on the average. At Gorwel Heights the mean temperature was 11.8C [+0.2] of the 30-y average. The highest maximum 17.3C was on the 3rd while the lowest minimum 6.8C was on the 23rd.

There were 12 days of missing published sunshine records at RAF Valley. The sunniest day in available records was on the 2nd with 10.5h.

In Llansadwrn the mean solar radiation was 6.64 MJ m ^-2 . The brighest day was on the 3rd having 12.67 MJ m ^-2 , the dullest day having 2.58 MJ m ^-2 was on the 28th. There were 6 sunless days.

November 2016

A dry monthy

Cooler with ice precipitation in the middle of the month; a very wet day on the 21st

Although the month had 110.5 mm of rainfall it was the 39th lowest in records since 1928. Averaging (86%) & [88%] it was lowest since 2014. The wettest day was on the 21st raining continuously for 21 hours 62.8 mm fell here and 54.6 mm at Gorwel Heights, but both totals beaten by the 82.0 mm at Gorddinog. The 62.8 mm that fell in Llansadwrn was the largest in a day in November and 5th largest on any day since before 1979 at the station. There were 6 (+2.0) days with no precipitation; 11 (+3.8) dry days; 19 (-3.8) rain days; 13 (-5.0) wet days; and 3 (-5.8) days with 5 mm, or more. Wet hours in Llansadwrn were 109 with an average fall of 1.0 mm and at Gorwel Heights 122 hours at an average of 0.9 mm where the total for the month was 108.2 mm.

Temperatures ran below average with the mean 6.9C (-1.9) & [-0.8] of averages lowest since 2010 ranked 6th since before 1979. Maxima showed the greatest anomalies with the mean 9.3C (-2.6) & [-1.1]. The highest maximum was 14.2C on the 14th and the lowest 5.9C on the 21st. Mean minima were also below average 4.4C (-1.3) & [-0.6]. The highest minimum was 11.7C on the 15th and the lowest 0.6C on the 16th there being no ground frost recorded. There were 13 days with ground frost, the lowest grass minimum was -5.4C on the 29th. At Gorwel Heights the mean temperature was 7.6C [-1.2] of average. The highest maximum was 16.2C on the 14th and the lowest minimum 1.8C on the 26th.

Autumn 2016

It was the driest autumn for over 60-years

Coolest since 2012, but 14th warmest since 1979

Mean temperatures 2.5C above 30-y average second highest on record, rainfall close to average with sunshine below average

A spell of 11 days (7-16th) with maxima >10C, 2 wet days (7th & 31st) otherwise it was fairly dry

A mild month with mean temperatures 2.5C above the 30-y average. The mean 7.8C (+2.1) & [+2.5] of averages was lowest since 2014, although lagging behind December 2015 that was the warmest on record with a mean 9.2C (+3.7) & [+3.9], nevertheless ranked second highest on record. The highest mean was 12.1C on the 8th and lowest 4.7C on the 4th. The mean maximum was 10.3C (+2.1) & [+2.5] second highest on record. The highest maximum 15.5C (+3.4) on the 14th was also second highest on record along with the lowest 7.2C on the 3rd; 16 days had maxima of 10C, or more. The mean minimum was 5.4C (+2.0) & [+2.5] was third highest on record while the highest 11.2C on the 8th was the third highest. There was no air frost, the fourth consecutive December with none, with the lowest minimum 0.8C (+2.3) on the 4th third highest on record. There were 13 days (-2.7) of ground frost, the lowest was -4.0C (+1.9) on the 4th most since 2014.

At Gorwel Heights the mean temperature was 9.1C [+2.5] of average. The highest maximum was 16.8C on the 6th and the lowest 7.1C on the 3rd and 26th. The highest minimum was 11.8C on the 8th with the lowest 2.5C on the 28th. There was no air frost.

Rainfall was 88.8 mm (53%) & [74%] of averages, least since 2010 ranking 26 since 1928. The wettest day was on the 7th having 20.0 mm closely followed by the 31st with 18.0 mm. There were 5 days (-0.10) with no precipitation; 13 dry days (+4.2); 18 rain days (-4.2); 13 (-5.3) wet days; and 5 days (-5.5) having had 5 mm, or more.

At Gorwel Heights rainfall was 53.2 mm [89%] of average with the largest fall 14.4 mm on the 31st, only 8.8 mm fell on the 7th when Llansadwrn had 20.0 mm. Dry days numbered 15; rain days 16; wet days 14; and 4 days had 5 mm, or more.