This summer was Ireland’s warmest season since records began in 1900, according to provisional data from Met Éireann.
The average temperate was almost 2 degrees higher than normal for the 2025 summer season, and 0.08 degrees hotter than the summer of 1995, the previous record holder.
The spring of 2025 was also the warmest on record. It is the first time since 1933 that temperature records were broken by consecutive seasons.
Met Éireann climatologist Paul Moore said: “Ireland is experiencing the effects of climate change, and our climate projections show that our climate is going to become warmer.”
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The national forecaster said the country’s current warming trend is “expected to continue into the future”.
“Maximum and minimum temperatures are projected to increase across all future scenarios annually and seasonally, with minimum summer temperatures expected to show a larger increase than maximum temperatures,” Met Éireann said.
The summers of 1995 and 2025 were the only ones where the average temperature exceeded 16 degrees. Provisional estimates from Met Éireann suggest an average temperature of 16.19 degrees for the summer, marginally above the 16.08 degree average in 1995.
All three months in 2025 were warmer than average. June and August were the fourth warmest on record, while July was the ninth warmest on record.
Unlike in 1976 and 1995, the summer of 2025 was not dominated by long, extended periods of hot and sunny weather. Heatwaves were relatively short-lived, but the record was broken because of other factors.
[ The Irish Times view on Europe’s hot summer: a clear weather warningOpens in new window ]
Dry soils from the warmest spring on record allowed heat to linger for longer, a marine heatwave pushed warm air up more consistently over Ireland and heat domes to the south of Europe occasionally extended as far as Ireland.
Another critical factor was warmer nights, with several long-standing stations having their highest number of warm nights on record.
This was a result of sea surface temperatures (SST) that were elevated around the coasts of Ireland and kept a blanket of warm air over Ireland at night.
Rainfall was below average in most places except in the western stations of Athenry (141 per cent of average), Valentia Observatory (113 per cent) and Newport (111 per cent of average).
The places that got the least rainfall over the summer were Moore Park (37 per cent of average) and Dublin Airport (43 per cent of average). Rainfall was almost as expected for the season at 98 per cent of the long-term average. June and July were slightly wetter than average while August was much drier.
In a statement, Met Éireann said the “consistency of the warmth, with heat building up quick and lingering”, contributed to this summer being the warmest on record.
Ireland is being affected by climate change, with an observed increase in air temperature of approximately 1.1 degrees since 1900, the forecaster said.
Climate change has the power “to turn previously unremarkable years into record-breaking ones, as baseline conditions steadily rise”, it said.
“This summer Ireland’s hot spells and European heatwaves, which might once have passed as pleasant spells of warm weather, are made more prominent by the heightened backdrop that climate change creates.”
Climate change also meant that minimum temperatures during the summer rose quicker than maximum temperatures.
Of the top 10 warmest summers, six of them have occurred since the millennium: 2025, 2023, 2022, 2018, 2013 and 2006.
