The extended range forecast, which includes the monthly and seasonal forecasts, can at times provide an insight into weather patterns in the months ahead. However, they should not be used for specific planning purposes as they have generally low skill compared with the 10-day forecast. This is because forecasts beyond one week become increasingly uncertain due to the chaotic nature of the atmosphere. Further information can be found here: Monthly and seasonal forecast explained.
Images: Shutterstock/gabriel12. Met Éireann HQ during Storm Emma 2018
MONTHLY FORECAST, ISSUED TUESDAY 30 DECEMBER 2025
Week 1 (Monday 05 January to Sunday 11 January)
Week 1 is indicating a strong signal for high pressure declining to the west and low pressure dominating conditions. There is a strong signal for below average temperatures with the chilly northerly airflow so frosty nights can be expected. There is a signal for predominantly settled conditions with lower than average rainfall signalled across much the country although higher than average rainfall is signalled near coasts.
Week 2 (Monday 12 January to Sunday 18 January)
While confidence in week 2 is lower, there is a signal for more unsettled conditions to develop as low pressure is set to take charge for week 2. Wetter than average conditions are forecast across the country with the south signalling the highest accumulations. Much of the country is signalling a return to normal temperatures for the time of year apart from parts of the north and midlands which still signal colder than normal temperatures.
Week 3 (Monday 19 January to Sunday 25 January)
There is increasing uncertainty in the forecast for week 3. There is a slight signal for low pressure to continue to dominate conditions again this week. Mean air temperatures look to return closer to average with rainfall amounts continuing to signal wetter than average conditions nationwide.
Week 4 (Monday 26 January to Sunday 01 February)
In week 4 the forecast confidence is low. There is a continued signal for low pressure over Ireland for the last week of January with predominantly unsettled conditions continuing. There is no signal for anomalous temperatures but a continuation of the wetter than average conditions is likely for most, although rainfall amounts in the north and northwest look likely to return closer to average for the time of year.
Seasonal Outlook for January February March 2026 (JFM):
The signal from the C3S seasonal models for Ireland during the JFM period is for above average temperatures. Rainfall amounts are less certain with the potential for wetter than average conditions overall.
Mean temperatures during JFM are signalled to be above average overall. Temperatures during the period are likely to trend between 0.5 and 1.0°C above normal, with the signal increasing through the period. However, colder than average periods, where all winter hazards are possible, could still occur at times throughout JFM, especially early on in the period.
There is a signal for above average rainfall overall, especially in the north and west of Ireland. This signal increases through JFM with March indicating the highest likelihood of above average rainfall out of the three months. Generally, there is potential for wetter and drier spells within the three months of JFM.
The sea surface temperatures (SSTs) around Irish coasts and over the Atlantic are expected to continue slightly above average during JFM. SSTs are trending 0.2 to 0.5 degrees higher than normal off the west and north coasts, with a trend of 0.5 to 1.0 degrees higher than normal off the south and east coasts.