Ireland had one of its warmest summers on record, says Met Éireann

Warmer than average summer is not down to high temperatures during the day but relatively warm nights

The summer of 2023 was among the five warmest on record, according to figures from Met Éireann.

It may not have felt that way following July’s washout, but temperatures were well above average in June and above average for August.

Moving into next week, Monday is set to be a dry and mild day with plenty of sunshine, and highest temperatures of 21-25 degrees in light southeast to east or variable breezes.

Met Éireann expects good spells of sunshine on Tuesday, although there is the chance of some heavy or thundery showers. Highest temperatures are due to be 20-24 degrees generally.

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The outlook further into the week is uncertain, with the high pressure set to gradually decline towards the east, allowing for some rain and showers to move in. Temperatures are expected to still hit the low 20s.

Paul Downes, an operational meteorologist at Met Éireann, said forecast models differ on next week’s outlook but a push of cooler air from the northwest will bring temperatures back down and unsettled weather towards the middle to end of the week.

“It’s quite short-lived,” says Mr Downes of the upcoming good weather, “but we are looking at some nice warm temperatures for this time of year.”

According to Mr Downes, a “blocking pattern” throughout the summer ensured that high pressure remained in southern Europe over Greece, Italy and Spain. “We’ve been plagued by low pressure over the last few months and a lot of rainfall,” he said.

A number of hurricanes, tropical storms and depressions in the Atlantic were “pumping warmer air into the upper atmosphere,” said Mr Downes, “allowing high pressure to build in from the east. That’s really what is bringing this warmer spell.”

Overall, the average summer temperature was 15.8 degrees, making it the hottest summer after 1995, 1976 and 2006.

The average summer temperature of 15.8 degrees is almost identical to that of 2018.

This summer was 0.3 degrees warmer than last year despite the summer of 2022 having a few days that were some of the hottest ever recorded in Ireland.

June was the warmest on record in most places, with the average temperature for the month exceeding 16 degrees for the first time. It was followed by a forgettable July which was the wettest on record in many places, but was not especially cold, with temperatures an average of between 0.6 and 0.8 degrees lower than normal.

August was a warmer month than normal almost everywhere but it too was wet, though most of the rain was concentrated in the first week.

Valentia Observatory in Co Kerry had an exceptionally wet summer, with 472mm of rain (177.2mm in August), which is 40 per cent more than average.

Met Éireann climatologist Paul Moore said the warm summer is not down to high temperatures during the day, but relatively warm nights.

Thirteen out of 25 weather stations recorded their highest minimum night-time temperature for summer on record.

Two named storms, storm Antoni, named by the UK Met Office, and storm Betty, named by Met Éireann, were the significant weather events of August.

The first week saw two low-pressure systems crossing the south of the country from west to east, bringing bands of rain or showers. But this was quickly replaced by “a more active low-pressure system”, storm Antoni, which crossed the country on the 4th and 5th.

A transient area of high pressure brought a few mostly dry days at the beginning of the third week, before storm Betty developed to the southwest of Ireland and moved rapidly towards the country on Friday 18th. This brought widespread heavy rain and strong winds, with thunderstorms and some flash flooding. The rest of the month saw low pressure to the north of Ireland, bringing further bands of rain or showers, sometimes thundery, interspersed with drier, sunnier periods.

The majority of monthly rainfall totals were above their 1981-2010 long-term averages (LTAs). The percentage of monthly rainfall ranged from 78 per cent at Mace Head, Co Galway to 163 per cent at Dublin Airport, Co Dublin.

The month’s wettest day was on Friday 18th during storm Betty. The number of rain days ranged from 15 days at Casement Aerodrome, Co Dublin to 29 days at Newport, Co Mayo.

While it was wet, above-average temperatures were recorded nearly everywhere. Nearly all mean air temperatures were above their LTA for the month. Average temperatures for the month ranged from 14.2 degrees (0.5 degrees above its LTA) at Knock airport, Co Mayo to 16.3 degrees (0.3 degrees above its LTA) at Shannon Airport, Co Clare.

The month’s lowest temperatures were recorded on Thursday 24th, with the lowest air minimum of 5.0 degrees reported at Markree, Co Sligo (5.7 below its LTA) and the lowest grass minimum reported at Claremorris, Co Mayo at 2.8 degrees.

Nearly all available sunshine totals were below their long-term averages. Monthly sunshine totals were lowest at Belmullet, Co Mayo with 99.5 hours (no LTA comparison). The highest number of daily sunshine hours recorded was 13.2 hours at Malin Head, Co Donegal on Thursday 17th. The number of dull days ranged from two days at a few stations to five days at both Shannon Airport, Co Clare and Valentia Observatory, Co Kerry.

Tim O'Brien

Tim O'Brien

Tim O'Brien is an Irish Times journalist

Ronan McGreevy

Ronan McGreevy

Ronan McGreevy is a news reporter with The Irish Times