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
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sued: 14/08/2026 11:00
Week 1 – Monday 17th August to Sunday 23rd August
High pressure is signalled to be centred in the mid-North Atlantic with lower pressure signalled over Scandinavia.
Generally warmer than average temperatures will continue across much of the country, with the strongest signal
covering southern and southeastern parts. Temperatures are signalled to be closer to average in parts of the west
and northwest. Drier than normal conditions look set to prevail across the midlands, south and west while near-toabove-
average rainfall is expected in the north and northeast, indicating the influence of the afore-mentioned low
pressure.
Week 2 – Monday 24th August to Sunday 30th August
Confidence in the forecast lowers into Week 2. There is a weak signal for higher than normal pressure to the
northwest of Ireland and lower than normal pressure over continental Europe. Rainfall is signalled to be near to
slightly above average in the south and east, with drier than normal conditions signalled in the west and
northwest. Temperatures look likely to be close to average overall, perhaps a little warmer than normal in coastal
parts of the south and east.
Week 3 – Monday 31st August to Sunday 06th September
There are no clear preferences towards high or low pressure in Week 3 so confidence in the forecast is very low
and reverts to climatology. Seasonal conditions are generally mild and changeable as the transition from summer
to Autumn takes place. Above average temperatures are signalled along with slightly wetter than average
conditions.
Week 4 – Monday 07th September to Sunday 13th September
Signals remain weak into week 4, although there is a very weak signal for relatively high pressure over the
European continent. Again, climatology seems like the most likely outcome at this stage with generally mild and
changeable conditions. Temperatures
Seasonal Outlook for September, October and November (SON)
The signal from the C3S seasonal models for Ireland during the SON period is for above average temperatures. Rainfall amounts will be close to or lower than normal in September but we will see a transition to wetter, more unsettled conditions in October and November.
Mean temperatures during SON 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 SON varies. There is potential for normal or slightly drier than normal conditions during September. However, there is a signal for wetter than average conditions in October and November.
The sea surface temperatures around Irish coasts are expected to be above average during SON, trending 0.5 to 2.0°C degrees higher than normal generally. Sea surface temperatures are expected to be highest in comparison to average during September.