A new study by climate experts at Maynooth University, in collaboration with Met Éireann, has revealed that human-induced climate change made Ireland’s record summer night-time temperatures this year 40 times more likely, reports RTE.
The findings indicate that warmer summers like this one are expected to become more frequent as climate change continues to raise global temperatures.
Summer 2025 has officially been declared the hottest summer ever recorded in Ireland, reports RTE.
The average combined temperature of day and night reached 16.19°C.
This surpassed the long-standing summer temperature record of 16.11°C, which had held since 1995.
Interestingly, daytime maximum temperatures were not particularly extreme and, according to researchers, did not match the heat seen in past record-breaking summers, reports RTE.
Instead, it was the unusually high temperatures during the night that pushed this summer into the record books.
Night-time is typically when summer temperatures are at their lowest. While this trend continued this year, what stood out was that overnight temperatures were, on average, the warmest on record, reports RTE.
Most Met Éireann stations recorded their highest ever mean minimum temperatures, according to the newly released report.
The research identifies three primary climate change-related factors that contributed to this development.
Firstly, following the warmest spring on record and an unusually dry period, Ireland’s soils were left parched, reports RTE.
Typically, moisture evaporating from the soil helps cool the air, especially at night. But this year, the lack of moisture significantly reduced that cooling effect.
The second factor was a series of marine heatwaves in nearby waters. An intense marine heatwave occurred in May and was followed by multiple others during the summer, reports RTE.
These events trapped more heat coming from southern Europe and North Africa and also diminished the usual cooling influence of the surrounding seas.
The third element was the presence of multiple “heat domes” across Europe, where temperatures were extremely elevated.
Together, these three influences on night-time temperatures were enough to transform an otherwise typical Irish summer into a historic one, the report states, reports RTE.
According to the study, average summer maximum and minimum temperatures in Ireland have increased by 1°C since pre-industrial times. It also finds that the kind of warm nights seen this year are now likely to occur roughly once every 15 years.
That makes them 40 times more common compared to pre-industrial conditions, when such nights would have only occurred once every 600 years. In effect, they were once-in-a-lifetime events, reports RTE.
If global temperatures continue on their current path—expected to rise by about 3°C by the century’s end—scientists warn that Ireland could see summers with similarly warm nights every second year.
The report also points out that even though daytime temperatures were not as extreme, they too are now nine times more likely to happen than in pre-industrial times, reports RTE.
This marks the first time a high-temperature rapid seasonal climate attribution study has been conducted for Ireland. The research was done by scientists at Maynooth University and Met Éireann, as part of the WASITUS project and in partnership with the World Weather Attribution team.
Dr Claire Bergin, Researcher for the WASITUS project, and Maynooth University, said: “The high temperatures experienced this summer are set to become more regular and warmer. Most houses in Ireland are not built with these rising temperatures in mind so preparing and adapting houses now will be important for the increasing regularity of future warm summers. In particular, for those warm summer nights which are set to become more regular,” reports RTE.
Paul Moore, Climatologist at Met Éireann, said: “The overall meteorological setup for Ireland during summer 2025 saw high pressure to the south and low pressure to the north leading to winds mostly between southerly and westerly. This is a fairly typical setup for Ireland in summer and led to near average sunshine and rainfall. The two previous warmest summers on record for Ireland, 1995 and 1976, were not typical at all. Both those summers were dominated by high pressure and were very dry and sunny by comparison. This means we have reached a point where the background warming due to climate change can transform an otherwise average season into a record warm season,” reports RTE.
Tell us your thoughts in the Facebook post and share this with your friends.
