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: 17/07/2026 13:00
Week 1 – Monday 20th July to Sunday 26th July
Blocking high pressure centred to the west of Ireland in the near Atlantic looks set to remain dominant through
much of this period, resulting in much drier than normal conditions and above-average temperatures for most.
Temperatures will be a little closer to normal in northern and northwestern coastal fringes.
Week 2 – Monday 27th July to Sunday 02nd August
The influence of high pressure looks set to decline in Week 2 compared to week 1, but there is still a strong signal
for high pressure to remain anchored out to the west or southwest of Ireland during the period, with lower
pressure signalled to the northeast in the vicinity of Scandinavia. Warmer than average temperatures and drier
than average conditions look set to persist over Ireland during this period.
Week 3 – Monday 03rd August to Sunday 09th August
Although confidence in the forecast tends to decline by week 3, there is a modest signal for high pressure to
reestablish through this period, perhaps from the south or east. Again, drier than average conditions combined
with above average temperatures are signalled for this period.
Week 4 – Monday 10th August to Sunday 16th August
A weak high pressure signal is signalled for northern parts during this period, with a more neutral pressure
anomaly signal further south. Temperatures look set to continue above average overall with rainfall near average
in many parts, but perhaps drier than average in parts of the west and southwest.
Seasonal Outlook for August, September and October (ASO):
The signal from the C3S seasonal models for Ireland during the ASO period is for above average temperatures. Rainfall is likely to continue below average during the period.
Mean temperatures during ASO are signalled to be above average overall. Temperatures are likely to trend between 0.5 and 1.0°C above average through the three months.
The rainfall forecast across ASO period is less certain, with a weak signal for below-average rainfall overall, especially during August and September.
The sea surface temperatures around Irish coasts are expected to be above average during ASO, trending 0.2 to 2.0 °C higher than normal generally. Sea surface temperatures are expected to be highest in comparison to average away from northwest coasts.