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: 22/09/2026 13:00
Week 1 – Monday 28th September to Sunday 04th October
For Week 1, our weather will likely be dominated by low pressure systems from the Atlantic bringing in spells of
rain and showers with the potential for windy conditions at times. The predominant southwesterly airflow will
mean temperatures will likely be above normal over the eastern half of the country with more average
temperatures further west. Rainfall accumulations are expected to be above normal throughout the country. There
is the possibility of wind and rainfall warnings being required during this period.
Week 2 – Monday 05th October to Sunday 11th October
More mixed conditions are indicated for Week 2 with high pressure building to the north, pushing low pressure
systems further south. An east to southeast airflow will result in above average mean air temperatures though
could lead to wetter than average conditions in the east and northeast but drier than average in the west.
Week 3 – Monday 12th October to Sunday 18th October
More unsettled conditions are indicated for Week 3 with low pressure systems dominating bringing wetter than
average conditions throughout the country. Temperatures will likely continue above normal.
Week 4 – Monday 19th October to Sunday 25th October
In Week 4, there is no strong signal for high pressure or low pressure to dominate but drier and warmer than
average conditions are signalled.
Seasonal Outlook for October, November, December (OND):
The signal from the C3S seasonal models for Ireland during the OND period is for above average temperatures. Rainfall amounts are also likely to trend above average with a strong signal for wet and unsettled conditions at times during OND.
Mean temperatures during OND are signalled to be above average overall. Temperatures during the period are likely to trend between 0.5 and 1.0°C above normal. However, colder than average periods, where winter hazards are possible, could still occur at times towards the end of OND.
The rainfall forecast for OND signals the potential for above average rainfall throughout the period, especially in the south. The highest likelihood for wetter than average conditions are signalled during November.
The sea surface temperatures (SSTs) around Irish coasts are expected to continue above average during OND, trending 0.2 to 1.0 degrees higher than normal generally.