Dry everywhere, sunny and warm in the South and East
June was dry overall with high pressure in control for most of the month. The high-pressure systems kept the Midlands, South and East of the country very dry, warm and sunny at times. Weak Atlantic weather fronts associated with low-pressure systems to the north of Ireland did affect the west coast on numerous occasions however, keeping in stubbornly cool and cloudy at times. The beginning of the first week saw weather fronts approaching Ireland from the west and south, giving some rain in these locations, but the rain generally died out before reaching the East and North of the country, as high pressure to the east of Ireland became dominant by the end of the week. Further weak weather fronts crossed the country during the second week, but rainfall amounts stayed generally low as high pressure, first to the east, then to the south, stayed in control. The third week again saw weak weather fronts affecting mainly the western half of the country for a few days before high-pressure, first to the south, then to the west, re-established control bringing mainly dry weather, but with a cooler northerly airflow. The beginning of the fourth week saw widespread rain as Atlantic weather fronts crossed the country from the northwest, but again amounts stayed relatively low in most places. High pressure to the west of Ireland dominated for the rest of the month keeping it dry everywhere.
Rainfall: Below average everywhere, especially in the Midlands and East
All monthly rainfall totals across the country were below their Long-Term Average (LTA). Percentage of monthly rainfall values ranged from 18% (the month’s lowest monthly rainfall total of 12.6 mm) at Dunsany, Co Meath to 81% (monthly rainfall total of 58.9 mm) at Finner, Co Donegal. Monthly rainfall totals were as much as 64.1 mm (71% of its LTA) at Newport, Co Mayo. Dublin Airport, Co Dublin also had 12.6 mm of rainfall for the month (19% of its LTA). The highest daily rainfall total was 21.5 mm at Finner, Co Donegal on Thursday 24th. The number of rain days ranged from 6 days at Phoenix Park, Co Dublin to 17 days at a few stations. The number of wet days ranged from 2 days at Dublin Airport, Co Dublin to 14 days at Knock Airport, Co Mayo. The number of very wet days ranged from zero days at a few stations to 2 days at Finner, Co Donegal. Mullingar, Co Westmeath had its driest June on record with 17.4 mm (23% of its LTA) (record length 71 years). Five stations had dry spells between the Saturday 29th May and Tues-day 22nd June. These were Dublin Airport, Co Dublin, Casement Aerodrome, Co Dublin, Phoenix Park, Co Dublin, Dunsany, Co Meath and Oak Park, Co Carlow. Two stations had absolute droughts between Saturday 29th May and Sunday 13th June. These were Dublin Airport, Co Dublin and Phoenix Park, Co Dublin.
Temperature: Above average in most places, coolest along the West coast
The majority of mean air temperatures were above their Long-Term Average (LTA) for the month. Deviations from mean air temperature ranged from -0.7°C (13.1 °C mean temperature) at Mace Head, Co Galway to 1.2 °C (14.7 °C the month’s highest mean temperature) at Phoenix Park, Co Dublin. Mean temperatures for the month were lowest at Knock Airport, Co Mayo with 12.2 °C (on its LTA). The month’s highest air temperature was reported at Phoenix Park, Co Dublin on Sunday 13th with a temperature of 25.6 °C (7.4°C above its LTA). Both the month’s lowest air and grass minimum temperature were recorded on Tuesday 22nd at Mount Dillon, Co Roscommon. The lowest air minimum was 1.3 °C (7.6°C below its LTA) while the lowest grass minimum was -5.1 °C. There was no air frost reported this month. The last June Frost Day occurred on Saturday 23 June 2007. Less than half of stations reported ground frost. The number of days with ground frost ranged from zero days at a few stations to 8 days at Mount Dillon, Co Roscommon.
Sunshine: Highest in the South and East
Nearly all available sunshine totals were above their Long-Term Average (LTA). Percentage of monthly sunshine values ranged from 92% (monthly sun-shine total of 144.0 hours) at Shannon Airport, Co Clare to 112% (monthly sunshine total of 179.7 hours) at Casement Aerodrome, Co Dublin. Monthly sunshine totals ranged from 99.1 hours (No LTA comparison*) at Belmullet, Co Mayo to 190.3 hours (No LTA comparison*) at Johnstown Castle, Co Wexford. The highest number of daily sunshine hours recorded this month was 15.3 hours at Valentia Observatory, Co Kerry on Wednesday 30th. The number of dull days ranged from 1 day at Shannon Airport, Co Clare to 11 days at Valentia Observatory, Co Kerry.
Wind: No sustained wind speeds greater than a Near Gale
Monthly mean wind speeds ranged from 5.4 knots (10.0 km/h) at Ballyhaise, Co Cavan to 12.2 knots (22.6 km/h) at Malin Head, Co Donegal. There were no days with gales, strong gales or storms reported this month. The months highest gust (2-second mean) on Thursday 10th at Belmullet, Co Mayo and Friday 25th at Malin Head, Co Donegal was 39 knots (72 km/h) while the month’s highest 10-minute mean wind speed on Thursday 10th at Belmullet, Co Mayo and Friday 25th at Malin Head, Co Donegal was 31 knots (57 km/h). The predominate wind direction during June 2021 was from the west.
The full report is available here