Click the button below for an Excel file giving daily data for 2026:-
June 2026 was very much a month of two halves: cool and much wetter than usual until the 17th and then warm/hot with minimal rain for the remainder.
The average maximum temperature of 21.6°C was 1.3°C above the Usk* average for June of 20.3°C, this being boosted by an official heatwave (21st to 26th) when the maximum temperature was 26°C or above for at least three consecutive days (6 days in this case). The temperature peaked at 33.7°C on the 25th and exceeded 30°C on the 23rd and 24th also. All three days “beat” the highest June temperature previously recorded in Penallt.
The highest June temperature recorded since records began in Penallt in 2011 was 30.8°C (19th and 21st in 2017), closely followed by 30.7°C on the 29th in 2019 and the 25th in 2020. This June was the third warmest on record, beaten by 2023 (22.8°C) and 2018 (22.2°C).
The month was also noted for overnight lows being such that two nights (24th and 25th – 20.2°C and 20.8°C respectively) were officially “tropical nights”, where the temperature didn’t drop below 20°C. The only other instance of this since records began in April 2011 was on August 19th 2022 where the low was 21.7°C.
June had only two very wet days (> 10mm) but many others had a decent sprinkling and the Penallt total rainfall rose to 79.8 mm, 33% above the Usk* June average of 60.2 mm. The wettest day was the 1st, with a fall of 19.4 mm. There were 10 days in the month when no measurable rain fell too. Overall, this was the sixth wettest June on record in Penallt, the wettest being 2012 when 248.2 mm were recorded.
May 2026 started with a dull and cold spell of 3 weeks and finished with a record-breaking spell of hot weather during which Penallt entered a meteorological heat wave lasting five days. The criterion for heat wave in Monmouthshire is for 3 consecutive days where the temperature exceeds 26°C and Penallt had five such days, 24th to 28th inclusive. The 26th had the highest temperature of all of 31.9 °C, beating the previous high for a May day in Penallt (26.5 °C on the 7th in 2018 and 1st last year) by an astonishing 5.4 degrees!
Maximum temperatures exceeded 20°C on 11 days. The lowest maximum was 11.6°C on the 18th. Overall, the average maximum temperature of 18.7°C was 1.2°C above the Usk average for May of 17.5°C, making it the third warmest May since 2011 (2018 and 2020 both had average maxima of 19.0°C).
The month was a little drier than usual and included 19 days on which no significant rain fell. The total rainfall of 66.2 mm was 93% of the Usk* average for May of 71.5 mm.
April 2026 was much drier and warmer than usual.
Overall, the average maximum temperature of 15.1°C was 1.1°C above the Usk average for April of 14.0°C with a peak of 23.2°C on the 8th. The minimum temperature was 1.1°C on the 6th and there were no days of air frost. It was the fifth warmest April in Penallt in the last 16 years.
There were 21 days when no rain (or a trace) fell, the wettest day being 15th when 15.4 mm fell. It was much drier than usual overall with the total rainfall of 39.8 mm being 59% of the Usk* average for April of 67.5 mm.
March 2026 was the driest month in Penallt since last August, the six months since then all having significantly higher rainfalls than average. The total rainfall was 62.8 mm, about 76% of the Usk* average for March of 83.1 mm.
There were 15 days on which rain fell (>0.2 mm), the wettest being the 12th with 32.8 mm.
It was a little warmer than usual too. Overall, the average maximum temperature of 11.6°C was 0.5°C above the Usk average for March of 11.1°C. The coldest by day was the 7th, with a maximum of 6.6°C, and the warmest was the 31st with a maximum of 18.4°C. There were no days when the minimum fell below zero.
February 2026 was about average for temperature by day, significantly warmer by night and very much wetter than usual. The month had one frosty morning when the temperature dropped to -1.4°C on the 14th. Overall, the average maximum temperature of 8.8°C was 0.3°C above the Usk average for February of 8.5°C with a maximum of 13.7°C on the 25th.
The average minimum temperature was 4.4°C (3.3°C above expected), a reflection on the continuous cloud cover during the month, broken only by the rare appearance of blue skies which allowed colder nights.
There were 6 days on which no significant rain (0.2 mm or less) fell, and a total monthly rainfall of 214.8 mm was 2.46 times the Usk* average for February of 87.4 mm. The wettest day was the 5th with 24.2 mm.
The meteorological winter (Dec/Jan/Feb) just ended had a total rainfall of 664.4 mm, or 98% above the Usk average of 336.9 mm. This made it the second wettest winter since Penallt records began in 2011, the wettest being 2013/14 with an incredible 777.8 mm
January 2026 was much colder and very much wetter than usual. The average maximum temperature of 6.4°C was 1.7°C below the Usk average for January of 8.1°C. The minimum temperature sank below 0°C on only two days however. The warmest day was the 11th (max = 10.6°C) and the coldest was the 5th with a maximum of 1.3°C.
The measured rainfall was 239.0 mm, was 87% above the Usk* average for January of 127.6 mm. This made January the second wettest January since Penallt records began in 2011 and the 8th wettest month overall in this time. Rain was measured on 25 days in the month, the wettest being the 27th when 42.4 mm fell.
* Usk is the nearest Met Office station for which long term averages (1981-2010) are available.