County Donegal climate

Monthly averages for Letterkenny, 2021–2025 · Ulster

Donegal, in the far north-west, is wet, windy and cool, with Malin Head taking the brunt of Atlantic storms. The hills and the west coast are very wet; the east around Letterkenny is more sheltered. Summer days are long, with light until late.

Rain: about 1211 mm falls in a year at Letterkenny, on roughly 200 days, making Donegal the 11th wettest of the 32 counties. October is the wettest month (129 mm) and May the driest (85 mm).

Temperature: July is the warmest month, with afternoons averaging 18°C, and January the coldest, with nights averaging 3°C. Frost is rare.

Sunshine: about 2212 hours a year, the 32nd sunniest of the 32 counties. May is the sunniest month (9.3 hours a day) and December the dullest (2.4).

Compare Donegal with its neighbours →

Rainfall

Average total rainfall each month, in millimetres. 1211 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 2212 hours a year.

Donegal and its neighbours
County	Rain mm/yr	Rain days	July high	January low	Sun h/yr
Donegal	1211	200	18°C	3°C	2212
Derry	1186	206	18°C	3°C	2255
Fermanagh	1216	197	19°C	2°C	2301
Leitrim	1231	192	19°C	3°C	2368
Tyrone	1200	200	18°C	2°C	2255

Recent extremes, 2021–2025

Hottest day: 28.1°C on 18 July 2022
Coldest night: −5.4°C on 10 January 2025
Wettest day: 39.2 mm on 27 July 2021
Wettest month: February 2022, 188 mm
Driest month: March 2025, 40 mm

Ireland's all-time records are on the records page.

Letterkenny month by month
Month	High °C	Low °C	Rain mm	Rain days	Sun h/day	Wind km/h
January	7	3	87	15	3.3	15
February	9	4	101	16	4.2	18
March	10	3	86	15	5.6	14
April	12	4	91	16	8.3	13
May	15	8	85	16	9.3	12
June	17	10	88	15	8.7	14
July	18	12	108	18	7.6	12
August	18	12	109	18	8.6	13
September	16	10	98	16	6.8	13
October	13	9	129	18	4.4	15
November	10	6	104	17	3.4	15
December	8	4	125	18	2.4	16
Year	13	7	1211	200	2212 h	14

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: Derry · Fermanagh · Leitrim · Tyrone. All counties: rainfall, temperature, sunshine.