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 05 DECEMBER 2025
Week 1 (Monday 08 December to Sunday 14 December)
Week 1 will remain unsettled with Atlantic low pressure systems dominating our weather. This will bring frequent spells of rain and windy conditions at times. Rainfall amounts will be higher than average nationwide. It will be milder than normal also, with frost unlikely during the week. With the unsettled conditions, there is a chance of wind or rain warnings through the week.
Week 2 (Monday 15 December to Sunday 21 December)
It will remain unsettled during week 2 with low pressure systems in the Atlantic continuing to steer spells of rain across the country. Rainfall amounts will remain higher than normal as a result, with the highest accumulations likely in the west and southwest. Temperatures will also continue above normal so the potential for frost will remain low.
Week 3 (Monday 22 December to Sunday 28 December)
While confidence decreases for week 3, current indications suggest that generally unsettled conditions will continue but there may be a chance of some longer dry interludes. Rainfall will generally be above normal but will be closer to average in eastern areas. Temperatures will decrease closer to normal so there will be a chance of frost by night.
Week 4 (Monday 29 December to Sunday 04 January)
Confidence is low by week 4. Current indications suggest that low pressure will remain nearby with potential for spells of rain and showers. However, rainfall will be near normal for most of the country, possibly decreasing slightly below normal in parts of the north. Temperatures will remain around normal so once again, there will be a chance of frost by night.
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.