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 16 DECEMBER 2025
Week 1 (Monday 22 December to Sunday 28 December)
Week 1 shows a signal for higher pressure centered over the country with temperatures around average or slightly below for this time of year. There is also a strong signal for lower than average precipitation accumulations. The current forecast indicates a return to more settled conditions.
Week 2 (Monday 29 December to Sunday 04 January)
A signal for higher pressure remains for week 2, albeit slightly weaker. Temperatures are expected to remain cooler than average, with the exception of the north where temperatures will be closer to average for this time of year. A signal for lower than average precipitation accumulations remains with a slight weakening in the signal for the eastern half of the country.
Week 3 (Monday 05 January to Sunday 11 January)
Uncertainty increases going to week 3, but current indications suggest a weak signal for higher pressure will persist. Temperatures are expected to return to average for the time of year, with precipitation accumulations looking to remain below average across the country.
Week 4 (Monday 12 January to Sunday 18 January)
Greater uncertainty in the forecast for week 4. There is no clear signal for whether lower or higher pressure will dominate. The current signal for temperatures indicates a return to average temperatures for the time of year. We also see a return to move average precipitation accumulations, with parts of the west and southwest possibly seeing greater than average totals.
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.