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Monthly climate in Letterkenny, Ireland

Last updated: July 31, 2025

Under the Köppen–Geiger climate classification Letterkenny features a oceanic climate (Cfb). Temperatures typically range between 6 °C (42 °F) and 15 °C (59 °F) through the year, but rarely can drop to -4 °C (25 °F) or can rise to as high as 28 °C (82 °F). The average annual precipitation amounts to about 1266 mm (49.8 inches) and receives 212 rainy days on the 1 mm (0.04 inches) threshold annually. Letterkenny enjoys an average of 2929 hours of sunshine throughout the year, and daylight varies from 7 hours 15 minutes to 17 hours 14 minutes per day.

Monthly average temperatures in Letterkenny, Ireland

The warmest months in Letterkenny are June, July and August, with daily mean temperatures ranging from 13 to 15 °C (56 - 59 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from 6 to 6 °C (42 - 44 °F) throughout the day. On average each year, Letterkenny experiences 1 days above 25 °C (77.0 °F) and 9 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Letterkenny. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to June 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Maximum14°C
(57°F)		15°C
(59°F)		17°C
(63°F)		21°C
(70°F)		25°C
(78°F)		27°C
(81°F)		28°C
(82°F)		23°C
(73°F)		24°C
(76°F)		19°C
(67°F)		15°C
(59°F)		13°C
(56°F)
Mean maximum12°C
(54°F)		12°C
(54°F)		14°C
(58°F)		17°C
(64°F)		22°C
(72°F)		21°C
(70°F)		24°C
(76°F)		21°C
(71°F)		20°C
(69°F)		17°C
(62°F)		14°C
(57°F)		12°C
(54°F)
Average high8°C
(46°F)		8°C
(46°F)		9°C
(49°F)		11°C
(53°F)		14°C
(58°F)		16°C
(61°F)		17°C
(64°F)		17°C
(63°F)		15°C
(60°F)		12°C
(55°F)		10°C
(50°F)		8°C
(47°F)
Daily mean6°C
(43°F)		6°C
(42°F)		6°C
(44°F)		8°C
(47°F)		11°C
(52°F)		13°C
(56°F)		15°C
(59°F)		14°C
(58°F)		13°C
(55°F)		10°C
(51°F)		8°C
(46°F)		6°C
(44°F)
Average low4°C
(39°F)		3°C
(38°F)		4°C
(39°F)		5°C
(41°F)		8°C
(46°F)		10°C
(51°F)		12°C
(54°F)		12°C
(54°F)		10°C
(51°F)		8°C
(47°F)		6°C
(42°F)		5°C
(40°F)
Mean minimum-1°C
(30°F)		-1°C
(30°F)		-1°C
(31°F)		1°C
(33°F)		3°C
(37°F)		6°C
(43°F)		8°C
(47°F)		8°C
(47°F)		6°C
(42°F)		3°C
(37°F)		1°C
(34°F)		0°C
(32°F)
Minimum-3°C
(27°F)		-3°C
(26°F)		-4°C
(25°F)		-1°C
(31°F)		1°C
(34°F)		5°C
(41°F)		7°C
(46°F)		7°C
(44°F)		3°C
(37°F)		1°C
(34°F)		-2°C
(29°F)		-2°C
(28°F)

Compare climate in Letterkenny with other places

Compare temperature, precipitation, sunshine, UV index in Letterkenny, Ireland with other places around the world.

Monthly average precipitation in Letterkenny, Ireland

Letterkenny usually has the most precipitation in August, October and December, with an average of 20 rainy days and 132 mm (5.2 inches) of precipitation per month. The driest months in Letterkenny are January, April and May. On average, 75 mm (3.0 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Letterkenny. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to January 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Average precipitation mm (inches)85 (3.3)123 (4.8)111 (4.4)59 (2.3)81 (3.2)102 (4.0)98 (3.9)146 (5.8)104 (4.1)124 (4.9)108 (4.2)124 (4.9)
Average precipitation days (≥ 1 mm)151618141617162219201920

Monthly sunshine hours in Letterkenny, Ireland

The sunniest months in Letterkenny are May, June and July, when the sun shines an average of 12 hours 40 minutes a day. Least sunny months in Letterkenny: January, November and December receive an average of 2 hours 51 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Letterkenny. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2017 to January 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Mean monthly sunshine hours6914319831239837738934727722011478
Mean daily daylight hours7h 51m9h 41m11h 53m14h 9m16h 10m17h 14m16h 39m14h 50m12h 39m10h 24m8h 22m7h 15m

Solar UV radiation in Letterkenny, Ireland

Letterkenny experiences the highest level of ultraviolet (UV) radiation in June, July and August, when the maximum UV index can reach values of 7 - 8, which corresponds to the High / Very High category of sun exposure. January, February and December are in the Low exposure category. In these months, the maximum values of the UV index do not exceed 2. For more detailed information, check out our hourly Letterkenny UV Index data.

Average daily maximum UV levels by month for Letterkenny. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2022 to January 2023.
 JanFebMarAprMayJunJulAugSepOctNovDec
UV Index (month maximum)124568875321