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 18 NOVEMBER 2025
Week 1 (Monday 24 November to Sunday 30 November)
Week 1 is indicating mixed conditions. There are hints that there will be some level of Atlantic mobility, indicating frontal passages, during the period as lower pressure is signalled to be slightly more pronounced over northern parts of Europe with comparatively higher pressure signalled over southern parts. The precipitation anomaly is signalling wetter than average conditions across the country. Mean air temperatures in week 1 will be mild with temperatures signalled to be above normal for the time of year.
Week 2 (Monday 01 December to Sunday 07 December)
While confidence in week 2 is lower, there appears to be a trend towards more blocked conditions for this period with higher than average pressure anomalies signalled over Scandinavia and northwestern parts of the Europe. This will bring predominantly settled conditions with lower than average rainfall signalled across much of the country. Mean air temperatures are signalled to continue above average in week 2.
Week 3 (Monday 08 December to Sunday 14 December)
There is increasing uncertainty in the forecast for week 3. There is a slight signal for low pressure in the Atlantic to influence conditions this week. The precipitation anomaly is signalling slightly wetter than average conditions for the south and east, with drier conditions in the west and north. Temperatures in week 3 are expected to be near to slightly above average for December.
Week 4 (Monday 15 December to Sunday 21 December)
In week 4 the forecast confidence is low. There is a continued signal for low pressure dominance this week with further unsettled conditions bringing wetter than average weather across much of the country. Mean air temperatures are continuing to signal slightly above average this week.
Seasonal Outlook for December January February 2025-26 (DJF):
The signal from the C3S seasonal models for Ireland during the DJF period is for above average temperatures. Rainfall amounts are less certain with the potential for slightly wetter than average conditions overall, with both wetter and drier periods possible within the three months.
Mean temperatures during DJF are signalled to be above average overall. Temperatures during the period are likely to trend between 0.5 and 1.0°C above normal. However, there is a higher likelihood of cold spells occurring compared to recent winters, with all winter hazards possible, throughout DJF, especially in December.
The rainfall forecast is less certain. There is a slight signal for above average rainfall overall, especially in the north and northwest of Ireland. Generally, there is potential for wetter and drier spells within the three months of DJF.
The sea surface temperatures (SSTs) around Irish coasts and over the Atlantic are expected to continue slightly above average during DJF. SSTs are trending 0.5 to 1.0 degrees higher than normal generally, with a trend of 0.2 to 0.5 degrees higher than normal off northern coasts.