Mild and wet first two thirds, cold and dry final third
December 2025 was a mixed month. Atlantic low pressure dominated the first two thirds, bringing mild, wet and sometimes windy conditions, followed by a cool, dry and less windy final third when high pressure to the north became established. Along with widespread gales and heavy rain, Storm Bram brought a very warm tropical maritime air-mass from the south with record high maximum daily temperatures for December at twelve stations, according to the latest Climate Statement from Met Éireann.
Key Figures:
- The national mean air temperature of 7.23°C (using the Island of Ireland dataset*) placed December 2025 24th warmest in 126 years.
- 7.23 °C is 1.33 °C above 1961-1990 long term average (LTA) and 1.02 °C above the most recent 1991-2020 LTA.
- Of the top ten warmest Decembers, four have occurred since 2001 (highest first 2015, 2018, 2024 and 2023). Of the top ten coolest Decembers, two have occurred since 2001 (lowest first 2010 and 2009).
- The national gridded average rainfall for December 2025 was 137.8 mm, ranked 42nd wettest in 85 years and 97% of its 1991-2020 LTA.
- The wettest December was in 2015 (323.0 mm) and driest was 1996 (52.1 mm).
December Climate Statement highlights
An active North Atlantic jet stream kept low pressure anchored to the northwest of Ireland during the first two thirds of December 2025. This setup sent numerous active weather fronts across the country from the southwest, interspersed with sunshine and showers. Several organised showery troughs also brought some intense thundery falls at times, especially in the Southwest and West. The South and parts of the West saw the bulk of the rainfall during this period with the East and North drier overall.
Storm Bram, named by Met Éireann, rapidly intensified as it approached Ireland from the Azores on Monday 8th and brought heavy rain and widespread gales on Tuesday 9th as the storm centre brushed the west coast of Ireland moving northwards. Bram, coming from a much warmer part of the Atlantic, brought a very warm tropical maritime airmass north over Ireland on Tuesday 9th, breaking daily maximum temperature records for December at numerous stations.
High pressure built to the north of Ireland for the final third of the month and kept it mostly dry in an easterly airflow. It was sunny at times, especially over the Christmas period but got progressively cooler and cloudier towards the end of the month.
Rainfall: Wettest in the South and parts of the West
December 2025 rainfall values were variable across the country. It was generally wetter than average in the South and parts of the West and drier than average in the East and North. Percentage of 1991-2020 Long-Term Average (LTA) monthly rainfall values ranged from 60% (78.0 mm) at Malin Head, Co Donegal to 161% (182.1 mm) at Johnstown Castle, Co Wexford (its wettest December since 2015). Monthly rainfall totals ranged from 48.4 mm (67% of its LTA) at Dublin Airport, Co Dublin to 198.2 mm (110% of its LTA) at Valentia Observatory, Co Kerry. The highest daily rainfall total was 51.1 mm at Johnstown Castle, Co Wexford on Sunday 14th (its highest daily fall for December since 2021 and 2nd highest on record (length 84 years)).
The number of rain days* ranged from 15 days at Dublin Airport to 25 days at Sherkin Island, Co Cork. The number of wet days* ranged from 12 days at Dublin Airport to 20 days at a few stations. The number of very wet days* ranged from zero days at a few stations to 9 days at Valentia Observatory, Co Kerry.
Rainfall % of 1991 – 2020 Monthly Average for December 2025 (Provisional) Total Monthly Rainfall (mm) for December 2025 (Provisional)
Temperature: Above average nearly everywhere, especially in the East
Nearly all mean air temperatures were above their LTA for the month. Deviations from mean air temperature ranged from -0.2 °C (7.9 °C mean temperature) at Valentia Observatory, Co Kerry to +1.9 °C at Casement Aerodrome, Co Dublin and Phoenix Park, Co Dublin (7.4 °C, 7.5 °C mean temperatures respectively). Mean temperatures for the month ranged from 5.7 °C (1.0 °C above its LTA) at Knock Airport, Co Mayo to 8.6 °C (0.4 °C above its LTA) at Sherkin Island, Co Cork.
The month’s highest daily temperature was reported at Phoenix Park, Co Dublin on Tuesday 9th with a temperature of 17.2 °C (its highest December maximum temperature on record (length 64 years)). The month’s lowest daily air minimum was recorded on Wednesday 31st at Ballyhaise, Co Cavan with -4.9 °C while the lowest grass minimum was -9.0 °C reported at Markree, Co Sligo on Christmas Day, Thursday 25th.
All stations reported ground frost during the month. The number of days with ground frost ranged from 2 days at Knock Airport, Co Mayo to 19 days at Markree, Co Sligo. More than half of stations reported air frost. The number of days with air frost ranged from zero days at ten, mostly coastal stations, to 10 days at Markree, Co Sligo. Twelve stations broke their maximum daily temperature records for December during storm Bram.
Dublin Airport, Co Dublin Temperature: Daily mean departure from LTA for December 2025 based on 09-09hr Max/Min values.
Valentia Observatory, Co Kerry Temperature: Daily mean departure from LTA for December 2025 based on 09-09hr Max/Min values.
Table 1: December 2025 station maximum daily temperature records provisionally broken or tied on Tuesday 09 December 2025: Difference from previous December station records shown.
Sunshine: Mostly above average, sunniest in the Southeast
All available sunshine totals were above their LTA. Percentage of monthly sunshine values ranged from 107% (51.3 hours) at Casement Aerodrome, Co Dublin to 114% (52.7 hours) at Shannon Airport, Co Clare. Monthly sunshine totals ranged from 29.1 hours (no LTA comparison*) at Belmullet, Co Mayo to 68.3 hours (no LTA comparison*) at Johnstown Castle, Co Wexford.
The highest number of daily sunshine hours recorded this month was 7.1 hours at both Dublin Airport, Co Dublin on Tuesday 2nd and Cork Airport, Co Cork on Christmas Day, Thursday 25th. The number of dull days* ranged from 12 days at Valentia Observatory, Co Kerry to 18 days at both Shannon Airport, Co Clare and Cork Airport.
Hours of Bright Sunshine observed at nine stations for each day of the month of December 2025, grouped by province relative to the highest number of hours possible by end of month (shaded box).
Wind: Strong gales reported during storm Bram
Monthly mean wind speeds ranged from 10.2 km/h (5.5 knots) at Moore Park, Co Cork to 30.5 km/h (16.5 knots) at Mace Head, Co Galway. Gales were reported on 12 days during the month, with up to strong gales reported on Tuesday 9th at four stations during storm Bram. The number of days with gales ranged from zero days at a few stations to 8 days at Mace Head, Co Galway. The number of days with up to strong gales ranged from zero days at most stations to 1 day at four stations. The month’s highest 10-minute mean wind speed of 47 knots (87 km/h) was reported at both Sherkin Island, Co Cork and Roches Point, Co Cork on Tuesday 9th during storm Bram. The highest gust was 64 knots (119 km/h) reported at Sherkin Island, Co Cork on Tuesday 9th during storm Bram.
Airmass Analysis chart 06 UTC 09 December 2025: Storm Bram moved north just to the west of Ireland steering up a very warm tropical maritime airmass from the south.
Full PDF report and charts are available here
Extreme values for December 2025 at synoptic stations.
Notes to Editor:
- *Issued by Met Éireann on Monday 5th January 2026. This report is based on available preliminary data from 25 principal weather stations operated by Met Éireann. Synoptic station data is midnight to midnight UTC. Long-Term Averages (LTAs) and “average” refer to the period 1991-2020 unless stated.
- A rain day is a day on which 0.2 mm or more of rainfall is measured. A wet day is a day with 1.0 mm or more of rainfall. A dull day is a day with less than 0.5 hours of sunshine. A very wet day is a day with 10.0 mm or more of rainfall.
- Climatological dry periods – An absolute drought is a period of 15 or more consecutive days to none of which is credited 0.2 mm or more of precipitation. A partial drought is a period of at least 29 consecutive days, the mean daily rainfall of which does not exceed 0.2 mm. A dry spell is a period of 15 or more consecutive days to none of which is credited 1.0 mm or more of precipitation (i.e. daily tot < 1.0 mm).
- A heatwave occurs where there are 5 consecutive days or more with maximum temperature over 25°C (that is, a daily maximum screen air temperature > 25° C).
- The ‘Island of Ireland’ dataset is 125 years long and runs between 1900 and 2023. For this dataset the long term averages from the 1961-1990 reference period are used for comparison as is standard for long-term climate change assessments.
- Sunshine data is from the Autosol Network. LTAs for these sites are currently not used for comparison purposes.
- For more information or interview opportunities with a Met Éireann spokesperson, please contact us at enq@met.ie.