Weather News Ireland

May 2021 across Ireland was a cold month especially the start of the month when the coldest May air temperature was record at the Met Eireann weather station at Mount Dillon, Co Roscommon of -4.0°C.

Four stations, had their coldest may on record. These were Mace Head, Co Galway (record length 17 years), Roches Point, Co Cork (record length 15 years), Mount Dillon, Co Roscommon (record length 15 years) and Gurteen, Co Tipperary (record length 13 years). Most long standing stations had their coldest May since at least 1996.

Northern Ireland

It was colder again across Northern Ireland with a temperature of -4.5 °C recorded overnight at Katesbridge (Down);

Most places were sunny and warm on the 30th, Magilligan reached a maximum of 23.0 °C the warmest temperature of the month across Northern Ireland .

All mean air temperatures across the country were below their Long-Term Average for the month. Deviations from mean air temperature ranged from -1.9 °C (9.0 °C mean temperature) at Markree, Co Sligo to -0.8 °C (10.0 °C mean temperature) at Phoenix Park, Co Dublin. Mean temperatures ranged from 8.9 °C (1.1 °C below its LTA) at Knock Airport, Co Mayo to 10.5 °C (1.2 °C below its LTA) at Sherkin Island, Co Cork (its coldest May since 1996). The month’s highest temperature was reported at Newport, Co Mayo on Sunday 30th May with a temperature of 23.1 °C. Both the month’s lowest air and grass minimum temperature were recorded on the 6th at Mount Dillon, Co Roscommon. The lowest air minimum was -4.0 °C (its lowest May temperature on record (length 15 years)) while the lowest grass minimum was -9.1 °C. All stations reported ground frost during the month.

Finner Donegal recorded the least amount of rain during may 2021

Percentage of monthly rainfall values ranged from 108% (the month's lowest monthly rainfall total of 83.2 mm) at Finner, Co Donegal to 241% (monthly rainfall total of 151.8 mm) at Roche's Point, Co Cork (its wettest May on record (length 15 years)). Monthly rainfall totals were as much as 174.0 mm (186% of its LTA) at Valentia Observatory, Co Kerry (its wettest May since 2006). The highest daily rainfall total was 30.9 mm at Moore Park, Co Cork on the 20th (its highest daily fall for May on record (length 57 years).

The number of wet days1 ranged from 10 days at Finner, Co Donegal to 22 days at Valentia Observatory, Co Kerry. The number of very wet days3 ranged from 2 days at a few stations to 8 days at Valentia Observatory, Co Kerry. Two station in County Cork had their wettest May since 1981. These were Cork Airport with 172.7 mm (210% of its LTA) and Moore Park with 130.8 mm (189% of its LTA). Two stations had their wettest May since 1993. These were Oak Park, Co Carlow with 123.6 mm (207% of its LTA) and Casement Aerodrome, Co Dublin with 111.5 mm (189% of its LTA).

EXTREME VALUES AT SYNOPTIC STATIONS MAY 2021

Rainfall

Highest total: 174.0 mm at Valentia Observatory, Co Kerry (186% of its LTA) (its wettest May since 2006)

Lowest total: 83.2 mm at Finner, Co Donegal (108% of its LTA)

Highest daily rainfall: 30.9 mm at Moore Park, Co Cork (45% of its monthly LTA) on Thu 20th (its highest daily fall for May on record (length 57 years))

Temperature

Highest mean monthly temperature: 10.5°C at Sherkin Island, Co Cork (1.2°C below its LTA) (its coldest May since 1996)

Lowest mean monthly temperature: 8.9°C at Knock Airport, Co Mayo (1.1°C below its LTA)

Highest Air temperature: 23.1°C at Newport, Co Mayo (7.5°C above its LTA) on Sun 30th, 23.0°C at Magilligan, Derry.

Lowest air temperature: -4.0°C at Mount Dillon, Co Roscommon (10.0°C below its LTA) on Thu 6th (its lowest May temperature on record (length 15 years)). Some places were frosty early on the 1st, with -4.5 °C recorded overnight at Katesbridge (Down)

Lowest grass minimum: -9.1°C at Mount Dillon, Co Roscommon on Thu 6th

Sunshine

Highest monthly total: 218.0 hrs (daily mean 7.03 hrs/day) at Belmullet*, Co Mayo

Lowest monthly total: 185.2 hrs (daily mean 5.97 hrs/day) at Gurteen*, Co Tipperary

Highest daily sunshine: 15.2 hours at both Dublin Airport, Co Dublin And Cork Airport, Co Cork on Sun 30th. The 31st was largely sunny, with Katesbridge (Down) recording 14.2 hours of sunshine.