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 22 APRIL 2025
Week 1 (Monday 28 April to Sunday 04 May)
Week 1 is indicating high pressure centred over the country dominating our weather into the start of May.
This will bring settled conditions with much drier than average conditions signalled especially in parts of
the west and southwest. Mean air temperatures in week 1 will be mild with temperatures above normal for
the time of year
Week 2 (Monday 05 May to Sunday 11 May)
Confidence in week 2 is lower with a less clear signal of atmospheric pressure, indicating a transition
away from the more settled conditions with more mixed weather expected. Temperatures will likely
continue above average and while precipitation amounts will likely remain drier than normal for much of
the country, they look to return closer to normal in parts of the north.
Week 3 (Monday 12 May to Sunday 18 May)
There is increasing uncertainty in the forecast for week 3. There is a slight signal for higher atmospheric
pressure close to the northwest of Ireland this week. This will bring more settled conditions and so mean
air temperatures are continuing to signal above average. The precipitation anomaly is also continuing to
signal above average rainfall amounts for most areas in week 3.
Week 4 (Monday 19 May to Sunday 25 May)
In week 4 the forecast confidence is low. There is no signal for either high or low pressure near Ireland.
Mean air temperatures look to continue above average again this week. Rainfall amounts look to be more
mixed this week with some areas signalling drier conditions once again while others signal close to
normal precipitation for the time of year.
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.