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 25 APRIL 2025
Week 1 (Monday 28 April to Sunday 04 May)
For week 1, high pressure east of Ireland looks to dominate, bringing a signal for much lower than average precipitation amounts for the time of year.A predominately southerly or southeast airflow will likely lead to temperatures trending above average for early May.
Week 2 (Monday 05 May to Sunday 11 May)
By week 2 however low pressure looks to become the dominant pressure pattern. This will likely lead to higher than average precipitation for the time of year.However, temperatures are again forecast to remain above average for the week as a whole.
Week 3 (Monday 12 May to Sunday 18 May)
For week 3, considerable uncertainty enters the forecast, with little to no signal for any dominating pressure pattern near the country.While precipitation forecasts are uncertain, there is still a signal for temperatures to continue above average for the time of year.
Week 4 (Monday 19 May to Sunday 25 May)
By week 4, uncertainty in the forecast increases once again, with again little to no signal in terms of a dominating pressure pattern.There is a slight signal for precipitation amounts to trend slightly above average, and for temperatures to also trend higher than average for mid to late May.
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.