Last month warmest May on record in Ireland, Met Éireann reveals

The Irish meteorological service said overall, using the island of Ireland dataset, May 2024 was the warmest May on record with an average temperature of 13.08 degrees.

This is 2.53 degrees above the 1961-1990 long term average (LTA) or 1.74 degrees above the 1991-2020 LTA for May.

Air temperature and rainfall values are averaged for each month over a 30-year period to obtain the long-term average.

This is only the second time (in 125 years of records at Ireland’s weather station recordings), that the May average temperature exceeded 13 degrees.

The previous warmest May was in 2008 with an average monthly temperature of 13.03 degrees, while the coldest was 102 years ago, in May 1923, with 8.67 degree average.

A total of 13 weather station’s recorded their warmest May on record, including at Phoenix Park, Co Dublin and Malin Head, Co Donegal.

The highest maximum temperature was reported on May 20 at Mount Dillon, Co Roscommon with a temperature of 24.6 degrees.

The month's lowest temperature was recorded on May 5 with the lowest air minimum reported at Moore Park, Co Cork with a temperature of 2.6 degrees.

Paul Moore, Climatologist with Met Éireann, said it “may not have felt to most people like the warmest May on record” due to night time temperatures increasing faster than daytime temperatures.

He stressed that the night time mean temperatures were responsible for bringing up the overall mean temperatures.

“There was quite a perception that it was a cloudy month. If it is warm and sunny it feels a lot warmer than when it is cloudy and warm,” he told the Irish Independent.

He added that this is the warmest May on record at the Phoenix Park’s station for three consecutive years.

However, due to the varying weather in Ireland, Mr Moore said it would be difficult to predict whether it will continue to be broken for a fourth consecutive time into next May.

He noted that it has also been a record high globally for 12 consecutive months.

“Our sea-surface temperatures in the north Atlantic have been at a record high now for over a year. That is feeding into our climate as well,” he said.

He explained that the warmest air and moisture as a result of this has led to increased temperatures over land.

“This has the climate change imprint on it however we can’t tell next May whether or not it will be broken as our weather conditions are so changeable,” he added.

Despite being the warmest May on record, Met Éireann said it was a “dull month” with sunshine values below average across the country.

In its climate statement for last month, it said: “May 2024 was very mild but also quite dull overall.”

It adds that rainfall totals were “mixed” with intense thundery downpours giving higher totals in the south and parts of the midlands while the east and northwest recorded a relatively dry month.

The majority of monthly rainfall totals across the country were below their 1981-2010 LTA. Percentage of monthly rainfall values ranged from 48pc (monthly rainfall total of 32.4 mm) at Ballyhaise, Co Cavan to 151pc (monthly rainfall total of 106.5 mm) at Mount Dillon, Co Roscommon.

Monthly rainfall totals ranged from 29.3 mm (50pc of its LTA) at Casement Aerodrome, Co Dublin to 124.7 mm (136pc of its LTA) at Knock Airport, Co Mayo.

The month’s wettest day was also recorded at Knock Airport, Co Mayo with 34.9 mm on Sunday 26th (its highest daily rainfall in May since 2005). The number of rain days ranged from 11 days at Mace Head, Co Galway to 18 days at Mullingar, Co Westmeath.

The number of wet days ranged from seven days at Dunsany, Co Meath to 13 days at a few stations. The number of very wet days ranged from zero days at Phoenix Park, Co Dublin to five days at both Roche’s Point, Co Cork and Cork Airport.