Mild and changeable
Atlantic low pressure pushed against high pressure over Scandinavia on several occasions during April. This brought some dry periods when the Scandinavian high pressure dominated and some wet periods when the Atlantic low pressure dominated. The first week began with a stalled front bringing rain to the East of the country as high pressure built over Scandinavia. A relatively dry few days gave way to Atlantic fronts pushing in from the west giving some rain mid-week. Another few mostly dry days at the end of the first week and beginning of the second week gave way to Atlantic low pressure dominating through the rest of the second week. A deep depression, named storm Noa by Météo-France, gave widespread wet and windy weather on the 11th and 12th. At the beginning of the third week, high pressure to the east and low pressure to the west steered a mild tropical maritime air mass over the country from the southwest, along with a band of frontal rain. This was followed by an easterly airflow between the 18th and 22nd as high pressure over Scandinavia moved towards Greenland. After several mostly dry days, frontal rain pushed in from the east on the 22nd. A few cooler days followed as the winds backed northerly and further bands of rain or showers crossed the country. Atlantic low pressure brought a warmer air mass up from the south again on the 26th and 27th, along with bands of mostly light rain or showers. The final few days of the month were showery with some heavy and thundery downpours breaking out, especially in the Midlands, North and East.
Rainfall: Near average overall, wettest in the Northeast and parts of the West
The Percentage of 1981-2010 Long-Term Average (LTA) rainfall values were variable across the country. Percentage of monthly rainfall values ranged from 68% (monthly rainfall total of 52.0 mm) at Cork Airport, Co Cork to 145% (monthly rainfall total of 76.4 mm) at Phoenix Park, Co Dublin (its wettest April since 2012). Monthly rainfall totals ranged from 49.4 mm (88% of its LTA) at Oak Park, Co Carlow to 121.1 mm (125% of its LTA) at Newport, Co Mayo. The month’s wettest day was also recorded at Newport, Co Mayo with 25.5 mm on Saturday 15th (its highest daily fall for April since 2013). The number of rain days ranged from 16 days at Oak Park, Co Carlow to 22 days at both Newport, Co Mayo and Knock Airport, Co Mayo. The number of wet days1 ranged from 10 days at both Mace Head, Co Galway and Roche’s Point, Co Cork to 18 days at Newport, Co Mayo. The number of very wet days3 ranged from zero days at Shannon Airport, Co Clare to 4 days at Newport, Co Mayo.
Rainfall % of 1981 – 2010 Monthly Average for April 2023 (Provisional)
Total Monthly Rainfall (mm) for April 2023 (Provisional)
Temperature: Above average everywhere
All mean air temperatures across the country were above their LTA for the month. Deviations from mean air temperature ranged from 0.4 °C (8.8 °C, 9.8 °C mean temperature) at Markree, Co Sligo and Sherkin Island, Co Cork respectively to 1.4 °C (9.6 °C mean temperature) at Phoenix Park, Co Dublin. Mean temperatures for the month ranged from 8.6 °C (1.2 °C above its LTA) at Knock Airport, Co Mayo to 10.4 °C (1.1 °C above its LTA) at Valentia Observatory, Co Kerry. All the month’s highest and lowest temperatures were recorded at Mount Dillon, Co Roscommon. Both the lowest air and grass minimum temperatures were reported on Tuesday 25th with an air minimum of -3.4 °C while the grass minimum was -8.9 °C. The high maximum was reported on Sunday 16th with a temperature of 21.3 °C. All stations reported ground frost during the month. The number of days with ground frost ranged from 1 day at a few stations to 17 days at Markree, Co Sligo. More than half of stations reported air frost. The number of days with air frost ranged from zero days at a few stations to 6 days at Mount Dillon, Co Roscommon.
Valentia Observatory, Co Kerry temperature: Daily mean departure from LTA for April 2023
Dublin Airport, Co Dublin temperature: Daily mean departure from LTA for April 2023
Sunshine: Dull in the South, sunny in the Northwest
All available monthly sunshine totals were below their LTA. Percentage of monthly sunshine values ranged from 92% (monthly sunshine total of 139.9 hours) at Casement Aerodrome, Co Dublin to 95% (monthly sunshine total of 146.7 hours) at Shannon Airport, Co Clare. Monthly sunshine totals ranged from 108.5 hours (No LTA comparison*) at Cork Airport, Co Cork to 166.0 hours (no LTA comparison*) at Malin Head, Co Donegal. The highest number of daily sunshine hours recorded this month was 14.0 hours at Malin Head, Co Donegal on Thursday 20th. The number of dull days2 ranged from 4 days at both Gurteen, Co Tipperary and Malin Head, Co Donegal to 7 days at a few stations.
Wind: Storm force winds reported during storm Noa
Monthly mean wind speeds ranged from 5.9 knots (10.9 km/h) at Ballyhaise, Co Cavan to 13.7 knots (25.4 km/h) at Malin Head, Co Donegal. Gales were reported on the 11th and 12th with strong gales and storm force winds reported on Wednesday 12th during storm Noa. The number of days with gales ranged from zero days at Dublin Airport, Co Dublin to 2 days at both Mace Head, Co Galway and Sherkin Island Co Cork. The number of days with strong gales ranged from zero days at most stations to 1 day at Roches Point, Co Cork, Sherkin Island, Co Cork and Mace Head, Co Galway, all on Wednesday 12th. The number of days with storms force winds was 1 day at Sherkin Island, Co Cork. Both the month’s highest gust and 10-minute mean wind speed were reported at Sherkin Island, Co Cork on Wednesday 12th during storm Noa. The highest gust was 66 knots (122 km/h) while the month’s highest 10-minute mean wind speed was 48 knots (89 km/h).
Maximum 10-minute Mean Wind Speeds (km/h) at each station for each day grouped by province and relative to their warning criteria and to their National Record
The full report is available here
April 2023 extreme values at synoptic stations
Recent Aprils in Ireland:
- 2016: Long-Term Average (LTA) rainfall values were variable. All stations reported below LTA mean air temperatures and monthly sunshine totals were mainly near or above.
- 2017: Mild and dry nearly everywhere. All rainfall totals were below their LTA, mean air temperatures were near or above, sunshine totals mostly below average.
- 2018: Unsettled, dull and wet. The majority of rainfall totals were above, most monthly mean temperatures were above average, sunshine totals were below and strong gales were reported.
- 2019: The majority of rainfall totals were above average, and nearly all mean temperatures were above. Sunshine totals were below average and Storm Hannah brought storm-force winds.
- 2020: Very dry, mild and sunny. All rainfall totals were below average, mean air temperatures across the country were above, sunshine totals were above average everywhere.
- 2021: Very dry, cool and sunny. All rainfall totals were below average, nearly all mean air temperatures were below, all sunshine totals were above.
- 2022: Mild, dry and sunny overall. Nearly all rainfall totals were below average while nearly all air temperatures were above. All sunshine totals were above and strong gales were reported.