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
Issued: 01/05/2026 10:00
Week 1 – Monday 04th May to Sunday 10th May
During Week 1, high pressure will dominate our weather. While there will be occasional spells of rain and showers,
overall there will be a good deal of dry weather with rainfall amounts likely to be below average as a result. It will
turn cooler, with air temperatures decreasing to around average or slightly below.
Week 2 – Monday 11th May to Sunday 17th May
It will turn more unsettled during Week 2 with low pressure having more of an influence over Ireland. This will
bring more frequent spells of rain and showers. Rainfall amounts will be slightly above average as a result. Air
temperatures will stay close to normal for most areas, but will be slightly above average in eastern areas.
Week 3 – Monday 18th May to Sunday 24th May
Confidence decreases into Week 3 but current indications suggest more mixed conditions with both dry spells and
spells of rain affecting the country. Rainfall accumulations will be near normal across most of the country with the
exception of some northern and northwestern areas. Rainfall amounts here will be slightly above normal. Air
temperatures are indicated to be approximately normal.
Week 4 – Monday 25th May to Sunday 31st May
There is considerable uncertainty for Week 4 with potential for both drier and wetter spells throughout the week.
As a result, current indications suggest that rainfall amounts will be approximately average with temperatures
around average also.
Seasonal Outlook for May, June and 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 with the possibility of precipitation trending near average overall.
Mean temperatures during MJJ are signalled to be above average overall. Temperatures are likely to trend between 0.2 and 1.0°C above average generally. The potential for warmer than average temperatures increases through June and July.
The rainfall forecast is less certain with no clear signal for above or below average rainfall overall. There is potential for both wetter and drier spells within the three months.
The sea surface temperatures around Irish coasts are expected to be above average during MJJ, trending 0.2 to 1.0°C degrees higher than normal generally. Sea surface temperatures are expected to be highest in comparison to average away from northwest coasts.