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 FRIDAY 26 DECEMBER 2025
Week 1 (Monday 29 December to Sunday 04 January)
High pressure is signalled to dominate our weather through Week 1 bringing predominately dry conditions but colder than average due to a chilly northeasterly airflow. There will be frosts at night, the extent of which will vary due to cloud cover. Fog will likely develop at times too and due to the mostly light airflow and low angle of the sun, it will be slow to clear during the days and may persist in areas.
Week 2 (Monday 05 January to Sunday 11 January)
Week 2 is also signalled to be dominated by high pressure though it may weaken and drift westwards. However, there is still a strong signal for much drier than normal conditions. Much of the country will still have below average temperatures with the chilly northeasterly airflow but parts of the north may return closer to normal. As in Week 1, frost and fog will develop at times.
Week 3 (Monday 12 January to Sunday 18 January)
Week 3 is expected to see a further shifting in position of the high pressure though it will likely still be the dominate driver of our weather. While the predominate airflow is still signalled to be northeasterly, it is likely that will shift later in the week. Overall, drier than average conditions are expected to continue but there is no signal for Week 3 to have colder than average temperatures.
Week 4 (Monday 19 January to Sunday 25 January)
In Week 4, the signals are not as strong but it is indicated that high pressure will still be mostly in charge of our weather but possibly positioned more to the north of the country with an easterly airflow developing. There is no signal for anomalous temperatures but a continuation of the drier than average conditions is likely.
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.