Recent Julys in Ireland:
- 2016: Long-Term Average (LTA) rainfall totals were variable, half of monthly mean air temperatures were above average and nearly all LTA sunshine totals were below average.
- 2017: Changeable with rain or showers most days. Most rainfall and sunshine totals were above average while the majority of air temperatures were below their LTA.
- 2018: Dry & warm with drought conditions. All monthly rainfall totals were below average, while all mean air temperatures and most of the sunshine totals were above their LTA.
- 2019: Warm overall, drier and sunnier in the South and East. The majority of monthly rainfall totals were below average while all mean air temperatures were above average and sunshine totals were variable.
- 2020: Cool and wet. All monthly rainfall totals were above average while mean air temperatures and sunshine totals were below.
- 2021: Hot, sunny with widespread heatwaves. Rainfall totals were variable and all mean air temperatures and sunshine totals were above average.
Warm and dry with record high maximum daily temperatures reported
July was warm and dry, especially in the South and East, with the Azores high dominating for most of the month. The first week began with several weak weather fronts crossing the country from the west bringing bands of showery rain, before high pressure built from the southwest giving mainly dry conditions to finish the week. High pressure stayed in control at the beginning of the second week, bringing mostly dry, warm and sunny conditions. An Atlantic weather front brought cloudier conditions with some rain on the 11th and 12th, before high pressure built again from the southwest towards the end of the week. The third week was dominated by a particularly hot period between the 17th and 19th when an exceptionally hot tropical continental air mass moved up from the south-southeast between low pressure to the west of the Iberian peninsula and high pressure over continental Europe. This brought record high maximum daily temperatures to nine synoptic stations on Monday 18th. A cold front brought outbreaks of thundery rain as it pushed the hot air mass away to the east at the end of the week. The forth week saw low pressure moving in from the west bringing bands of rain or showers across the country on the 23rd and 24th, before high pressure built again from the southwest, keeping it mostly dry for the second half of the week. The month finished with Atlantic weather fronts moving in from the west bringing further bands of rain or showers.
Rainfall: Below average everywhere, lowest in the South
All monthly rainfall totals across the country were below their 1981-2010 Long-Term Average (LTA). Percentage of monthly rainfall values ranged from 31% (the month’s lowest monthly rainfall total of 20.7 mm) at Shannon Airport, Co Clare (its driest July since 1989) to 82% (monthly rainfall total of 66.3 mm) at Malin Head, Co Donegal. Monthly rainfall totals were as much as 73.6 mm (81% of its LTA) at Finner, Co Donegal. The month’s wettest day was also recorded at Finner, Co Donegal with 24.8 mm on Sunday 24th. The number of rain days ranged from 6 days at Oak Park, Co Carlow to 22 days at both Malin Head, Co Donegal and Finner, Co Dongeal. The number of wet days1 ranged from 4 days at Oak Park, Co Carlow to 13 days at both Newport, Co Mayo and Malin Head, Co Donegal. The number of very wet days3 ranged from zero days at a few stations to 4 days at Athenry, Co Galway. Six stations had dry spells6 between 2nd and 22nd July lasting between 17 and 21 days. These were Sherkin Island, Co Cork and Claremorris, Co Mayo (17 days), Athenry, Co Galway (19 days), Ballyhaise, Co Cavan (20 days), Oak Park, Co Carlow, Mount Dillon, Co Roscommon and Mullingar, Co Westmeath (21 days).
Temperature: Above average everywhere, record high maximum daily temperatures reported at nine stations
All mean air temperatures across the country were above their LTA for the month. Deviations from mean air temperature ranged from 0.1 °C (15.3 °C and 15.2 °C mean temperature) at both Mace Head, Co Galway and Markree, Co Sligo respectively to 1.7 °C (17.3 °C the month’s highest mean temperature) at Phoenix Park, Co Dublin. Mean temperatures for the month were lowest at Malin Head, Co Donegal with 14.7 °C (0.3 °C above its LTA). The month’s highest temperature was reported at Phoenix Park, Co Dublin on Monday 18th with a temperature of 33.0 °C (the station’s highest daily maximum temperature ever recorded from records going back to 1881 (subject to further quality control and assessment) and the second highest temperature ever recorded in Ireland).
The month’s lowest air minimum was recorded on Friday 29th at Mount Dillon, Co Roscommon with 6.4 °C while the lowest grass minimum was 2.0 °C reported at Dublin Airport, Co Dublin on Wednesday 27th. There was no air or ground frost reported this month. Along with Phoenix Park, eight other stations reported their highest daily maximum temperature, for any month, on record, all on Monday 18th. These were Casement Aerodrome, Co Dublin (record length 58 years) with 31.9 °C, Mount Dillon, Co Roscommon (length 14 years) with 31.4 °C, Gurteen, Co Tipperary (length 14 years) with 31.0 °C, Ballyhaise, Co Cavan (length 17 years) with 30.8 °C, Athenry, Co Galway (length 12 years) and Dunsany, Co Meath (length 48 years) with 30.5 °C, Mullingar, Co Westmeath (length 72 years) with 30.4 °C and Dublin Airport, Co Dublin (length 80 years) with 29.6 °C. One station had its highest July daily maximum temperature on record. This was Shannon Airport, Co Clare (length 76 years) with 30.8 °C.
Sunshine: Highest in the Southeast, lowest in the Northwest
Nearly all available sunshine totals were below their LTA. Percentage of monthly sunshine values ranged from 97% (monthly sunshine total of 135.3 hours) at Shannon Airport, Co Clare to 99% (monthly sunshine total of 152.3 hours) at Casement Aerodrome, Co Dublin. Monthly sunshine totals ranged from 90.2 hours (No LTA comparison*) at Belmullet, Co Mayo to 186.7 hours (No LTA comparison*) at Johnstown Castle, Co Wexford. The highest number of daily sunshine hours recorded this month was 15.7 hours at Johnstown Castle, Co Wexford on Sunday 10th. The number of dull days2 ranged from 2 days at Dublin Airport, Co Dublin to 9 days at Belmullet, Co Mayo. (At time of print, sunshine data was not complete for Gurteen, Co Tipperary, Malin Head, Co Donegal and Johnstown Castle, Co Wex-ford).
Wind: Not significantly strong
Monthly mean wind speeds ranged from 4.7 knots (8.7 km/h) at Ballyhaise, Co Cavan to 11.8 knots (21.9 km/h) at Malin Head, Co Donegal. There were no days with gales, strong gales or storms reported this month. Both the month’s highest gust and 10-minute mean wind speed were reported at Malin Head, Co Donegal on Monday 25th. The highest gust was 40 knots (74 km/h) while the month’s highest 10-minute mean wind speed was 30 knots (55 km/h).
The full report is available here