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 21 NOVEMBER 2025
Week 1 (Monday 24 November to Sunday 30 November)
Confidence is high for week 1, with mixed and changeable weather to be expected. High pressure centred to the southwest of Ireland will lead to a good lot of dry weather early in the week, but low pressure to the northwest will send in spells of rain over the following couple of days and breezy conditions, with mixed weather for the rest of the week. There’ll be some spells of sunshine, but some showers or rain at times too, with the chance of hail and thunder, especially in the northwest. Overall rainfall amounts will be around average in many areas, or possibly a little below in some areas, but rainfall amounts will be higher than average in parts of the west and northwest. Mean air temperatures will be around average in many areas, a little higher than normal in the north and west, while they’ll be a little lower in the east. It looks like there’ll be very little in the way of frost.
Week 2 (Monday 01 December to Sunday 07 December)
During week 2, the first week of the meteorological Winter, there’s reasonable confidence that a changeable pattern of weather will continue. There’ll be drier spells of weather, but outbreaks of rain too, which will be heavy at times. Overall most areas will see around average amounts of rainfall to a little above. It’ll be drier though in the east and north, with below average amounts of rainfall expected in these areas. It’ll be milder than average across the country, with not much in the way of frost expected.
Week 3 (Monday 08 December to Sunday 14 December)
While confidence drops a little, it looks like week 3 will see high pressure to the east dominating a little more. This will lead to a good deal of dry, albeit most likely cloudy weather overall. Low pressure to the southwest will send in rain and drizzle at times too. Overall it looks like rainfall amounts will be lower than average and while it’ll be cooler than week 2, it’ll still be relatively mild for the time of year. There’s the likelihood of some frost by night under clearer breaks, but it’s unlikely to be widespread.
Week 4 (Monday 15 December to Sunday 21 December)
During week 4, while confidence lowers a little more, there is a signal for low pressure to play a more dominant role. This will lead to spells of wet and potentially windy weather. Some of the rain will be heavy, with some heavy showers at times too and a chance of hail. Overall it looks like rainfall amounts will come in a little above normal. Temperatures are likely to drop to around average for the time of year, with the chance of some frost in any drier, calmer, clearer interludes.
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.