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 06 MAY 2025
Week 1 (Monday 12 May to Sunday 18 May)
Strong signal for high pressure to be dominant through this period. Much drier than normal conditions look likely, along with generally warmer than average temperatures.
Week 2 (Monday 19 May to Sunday 25 May)
There’s an increased chance of more changeable conditions through this period as high pressure becomes more focussed to the west of Ireland. Potentially wetter than average conditions are possible near western and southwestern coasts with near average or drier than average conditions elsewhere. Warmer than average temperatures are signalled through this period.
Week 3 (Monday 26 May to Sunday 01 June)
A more changeable or unsettled regime is favoured for this period with a signalled trend towards lower pressure. Wetter than average conditions look set to prevail, though mean temperatures are expected to stay generally near or above average.
Week 4 (Monday 02 June to Sunday 08 June)
There is a weak signal for low pressure centred to the northwest of Ireland through this period with higher pressures centred over the continent. Above average rainfall and temperatures are predicted.
SEASONAL OUTLOOK FOR May June July (MJJ)
The signal from the C3S seasonal models for Ireland during the MJJ period is for above average temperatures. Rainfall amounts are less certain but there is potential for spells of wetter than average conditions in May.
Mean temperatures during MJJ are signalled to be above average overall. Temperatures are likely to trend between 0.5 and 1.0°C above average generally.
The rainfall forecast is less certain. While there is a chance of wetter than average conditions in May, generally there is potential for both wetter and drier than normal conditions through MJJ.
The sea surface temperatures around Irish coasts and over the Atlantic are expected to be above average during MJJ, trending 0.5 to 2.0°C degrees higher than normal generally. Sea surface temperatures are expected to be highest in comparison to normal off the south and west coasts.