County Antrim climate
Monthly averages for Belfast, 2021–2025 · Ulster
Antrim is in the north-east, in the lee of the rest of Ireland, so Belfast and the Lagan valley are relatively dry. The Antrim plateau and glens are wetter and colder, and the north coast is windy and cool.
Rain: about 1047 mm falls in a year at Belfast, on roughly 175 days, making Antrim the 24th wettest of the 32 counties. October is the wettest month (117 mm) and January the driest (62 mm).
Temperature: July is the warmest month, with afternoons averaging 19°C, and January the coldest, with nights averaging 2°C. Frost is rare.
Sunshine: about 2637 hours a year, the 5th sunniest of the 32 counties. June is the sunniest month (11.1 hours a day) and December the dullest (2.9).
Rainfall
Average total rainfall each month, in millimetres. 1047 mm a year.
Temperature
Bars run from the average night-time low to the average daytime high, in °C.
Sunshine
Hours of sunshine on an average day in each month. About 2637 hours a year.
Recent extremes, 2021–2025
- Hottest day: 28.1°C on 12 July 2025
- Coldest night: −4.3°C on 9 January 2021
- Wettest day: 32.8 mm on 19 October 2025
- Wettest month: December 2023, 177 mm
- Driest month: April 2021, 17 mm
Ireland's all-time records are on the records page.
| Month | High °C | Low °C | Rain mm | Rain days | Sun h/day | Wind km/h |
|---|---|---|---|---|---|---|
| January | 7 | 2 | 62 | 11 | 4.0 | 16 |
| February | 9 | 4 | 78 | 13 | 4.6 | 19 |
| March | 10 | 4 | 75 | 15 | 6.7 | 15 |
| April | 12 | 5 | 72 | 14 | 9.2 | 14 |
| May | 15 | 8 | 80 | 14 | 10.8 | 12 |
| June | 18 | 10 | 82 | 15 | 11.1 | 13 |
| July | 19 | 12 | 90 | 17 | 10.1 | 12 |
| August | 19 | 12 | 96 | 18 | 10.0 | 13 |
| September | 16 | 10 | 110 | 14 | 7.7 | 14 |
| October | 14 | 9 | 117 | 16 | 5.1 | 16 |
| November | 10 | 5 | 81 | 14 | 4.3 | 16 |
| December | 8 | 4 | 104 | 15 | 2.9 | 17 |
| Year | 13 | 7 | 1047 | 175 | 2637 h | 15 |
Figures are averages for 2021–2025 at each county town, from the ERA5 weather reanalysis via Open-Meteo. They describe typical lowland weather in each county; hills and exposed coasts are wetter and windier.
Bordering counties: Armagh · Derry · Down · Tyrone. All counties: rainfall, temperature, sunshine.