December 2025: Warmer, Drier, and Much Sunnier Than Average
Record-Breaking Calendar Year 2025: Second Warmest Year on Record at Armagh, Drier and Much Sunnier Than Average
Armagh Observatory reports that December 2025 was warmer, drier, and much sunnier than average. With 54.7 hours of strong sunshine, it was the sunniest December at Armagh for three years and the tenth sunniest December on record.
Taking 2025 as a whole, this was the second warmest year on record at Armagh, with an average temperature of 11.0 degrees Celsius (51.8 Fahrenheit). This was only slightly cooler, by 0.1°C, than the record-breaking year of 2023, which had an average temperature of 11.1°C. With 1,464.1 hours of strong sunshine, 2025 was also the fourth sunniest year on record at Armagh and the sunniest calendar year there for 66 years, since the record-breaking year of 1959, which recorded 1,512.3 hours.
Spring 2025 was the warmest and sunniest spring on record at Armagh, with an average temperature of 10.7°C and 617.1 hours of strong sunshine. Summer 2025 was the equal warmest summer on record, with an average temperature of 16.5°C, matching summer 1995.
The average temperature for December 2025 was 6.65°C (44.0°F), approximately 2.0°C warmer than the 225-year long-term December average at Armagh (4.64°C) and 1.4°C warmer than the most recent 30-year average (1991–2020) of 5.23°C. This made December 2025 the equal 29th warmest December on record, shared with December 2013.
The highest maximum air temperature recorded during the month was a very mild 14.7°C on the 9th. This was followed by 14.5°C shortly before the 09:00 GMT observation on the same day, attributed to the 8th, and by 13.6°C on the afternoon of the 14th. The 9th was the warmest December day at Armagh since 7 December 2016. The first three weeks of the month were much warmer than average, before cooler, more wintry conditions set in around Christmas Day and continued into the first ten days of January.
The lowest maximum air temperature, typically the coolest day, was 4.7°C on the 29th. This was followed by 5.1°C attributed to the 31st, though it occurred in the early hours of 1 January 2026, and by 6.2°C attributed to the 27th.
The highest minimum air temperature, usually the warmest night, was 8.2°C attributed to the 11th, though it occurred at approximately 22:15 GMT on the previous evening. This was followed by 8.1°C on the 10th and 7.7°C shortly before the 09:00 GMT observation on the 23rd. The lowest minimum air temperature was −3.4°C on the 31st, followed by −1.2°C on the 16th and −0.9°C attributed to the 17th but occurring shortly after the 09:00 GMT reading on the 16th. A fourth air frost of −0.3°C occurred in the early hours of the 27th.
There were 14 ground frosts during December. The lowest ground temperatures were −8.5°C on the 31st, −7.4°C on the 27th, and −6.7°C on the 16th.
Total precipitation for the month was 71.8 mm, including four trace values, or 71.6 mm when trace values are excluded. This was approximately 92% of the 183-year long-term December average at Armagh and 88% of the most recent 30-year average, confirming that December 2025 was drier than average.
The wettest day was the 5th, with 14.6 mm of precipitation, followed by 10.4 mm on the 18th and 8.2 mm on the 8th.
A rainbow was observed around lunchtime on the 8th, and bats were seen flying along the Observatory driveway during the early evening of the same day. The following day was windy, with occasional strong gusts associated with Storm Bram. Very small hail was observed on the afternoon of the 18th during heavy showers. No snow or sleet was recorded during the month.
With 54.7 hours of strong sunshine, December 2025 had approximately 44% more sunshine than the long-term December average and 27% more than the most recent 30-year average. The sunniest day was the 2nd, with 6.0 hours of sunshine, followed by the 26th with 5.9 hours, and the 12th, 16th, and 24th, each with 5.5 hours.
Looking at the year as a whole, every month except January and September was warmer than average. Several months, including March, April, May, July, and August, were much warmer than average. The warmest months were June, July, and August, with average temperatures of 15.3°C, 17.1°C, and 17.0°C respectively. Each month from March to August ranked among the twelve warmest on record for its respective month at Armagh.
These conditions resulted in 2025 becoming the second warmest year on record at Armagh. The ten warmest years recorded there are now 2023, 2025, 2022, 2007, 2024, 2021, 2006, 1949, 2017, and 1997. Six of these have occurred within the last ten years. The three warmest days of the year were 12 July (29.7°C), 20 June (29.3°C), and 12 August (27.9°C).
Total annual precipitation was 761.7 mm, including 40 trace values. This was approximately 93% of the long-term annual average and 92% of the most recent 30-year average, making 2025 slightly drier than average overall. A drier winter, spring, and summer were offset by a wetter-than-average autumn.
Annual sunshine totalled 1,464.1 hours, around 16% above the long-term average and 14% above the most recent 30-year average. This made 2025 the fourth sunniest year on record at Armagh. The five sunniest years are 1959, 1911, 1905, 2025, and 1919.
The sunniest months of the year were May, with 285.4 hours of sunshine; April, with 212.0 hours; and August, with 153.6 hours.
These data refer to observations made at Armagh Observatory, which has been recording the weather since 1795.
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