September 2025: Wettest Month of the Year So Far
September 2025 was the wettest month of the year so far and cooler than average across Ireland, according to Met Éireann.
Rainfall exceeded the long-term average at all stations, making it the 18th wettest September since records began in 1940. The highest daily total was 31.0 millimetres at Johnstown Castle in Wexford on 19 September.
Although some warm days were recorded, including 20.9 degrees Celsius at Shannon Airport on 9 September and Oak Park in Carlow on 17 September, temperatures were generally below average. Atlantic low-pressure systems dominated, bringing frequent rain and cooler northerly winds.
Rainfall was highest in the south-west, north-west and south-east. Valentia Observatory in Kerry recorded 218 millimetres for the month, its wettest September since 2006. Newport and Knock Airport in Mayo experienced 25 days of rain, while Roches Point in Cork had 19. Very wet days peaked at 10 at Newport.
Sunshine totals were above average in most areas. Cork Airport recorded the most sunshine at 160.8 hours, while the highest single-day total was 11.1 hours at Johnstown Castle on 22 September.
Strong gales were reported at several coastal stations. Mace Head in Galway recorded the highest gust at 109 kilometres per hour on 15 September. Ground frost occurred at more than half of stations with the lowest temperatures recorded at Mount Dillon in Roscommon.
The first two thirds of the month were dominated by Atlantic low pressure, bringing spells of rain and showers. High pressure returned in the final third, bringing drier and sunnier conditions before Atlantic systems moved back in at the end of the month. Overall, it was the coolest September since 2018 at thirteen stations.
