Letterkenny climate — normals and trends
Letterkenny (Ireland) has a temperate oceanic climate (Cfb) under the Köppen-Geiger classification. Its mean annual temperature is 9.3 °C and it receives 1,142 mm of precipitation per year.
These figures are normals computed over 86 complete calendar years, from 1940 to 2025, using ERA5 reanalysis data from the Copernicus programme.
The warmest month is July (14.2 °C on average) and the coldest is January (4.7 °C). Rainfall peaks in December.
Letterkenny averages 19 frost days, 0 hot days (≥ 30 °C) and 208 rainy days per year.
Letterkenny has warmed by +0.9 °C between 1940 and 2025, or +0.10 °C per decade. This trend is statistically significant.
The number of frost days there went from about 28 to 10 per year over the period.
The hottest day of the period reached 28.8 °C (on 19 July 2006) and the coldest -12.7 °C (on 1 March 1947).
Data from ERA5 reanalysis (Copernicus Climate Change Service), redistributed under a CC-BY 4.0 licence. Normals are recomputed whenever the archive is updated.
Climate normals · ERA5
LetterkennyUlster
- coords
- 54.95°, -7.73°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
9.3°C
Average daily high
11.8°C
Average daily low
6.7°C
Annual rainfall
1,142mm
Sunshine / day
7.1h
Mean relative humidity
83%
Average peak wind
23.2km/h
Seasonal range
9.5°C
Frost days (< 0 °C)
19 d/yr
Hot days (≥ 30 °C)
0 d/yr
Rainy days (≥ 1 mm)
208 d/yr
Annual snowfall
21.8 cm
Average feels-like high
8.8 °C
Average feels-like low
3.3 °C
Average peak gust
49.6 km/h
Tropical nights (≥ 20 °C)
0 d/yr
Solar radiation
9.3 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+0.9 °C
since 1940
+0.1 °C per decade · r² = 0.24 · p = < 0.001
Trend fitted by linear regression (ordinary least squares) on annual means. A trend is shown only when it is statistically significant (p < 0.05).
A climograph overlays rainfall (bars) and temperature (line): the standard reading in climatology, where you can see at a glance whether the warm season is also the dry one.
Records for the period
Hottest day
28.8 °C
19 July 2006
Coldest day
-12.7 °C
1 March 1947
Wettest day
50 mm
5 December 2015
Windiest day
71.5 km/h
26 December 1998
Strongest gust
158.4 km/h
26 December 1998
Hottest feels-like
32.7 °C
29 July 1948
Coldest feels-like
-17.3 °C
1 March 1947
Snowiest day
21.8 cm
30 March 2010
Sunniest day
17.0 h
9 June 1941
Normals computed over complete calendar years 1940–2025.
A specific year
Pick a year and see how it compares to normal — warmer, drier or more extreme than usual?
Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | 7.1 °C | +0.4 °C | 58 mm | -42 mm |
| Feb | 8.2 °C | +1.0 °C | 97 mm | +16 mm |
| Mar | 11.0 °C | +2.2 °C | 34 mm | -53 mm |
| Apr | 14.5 °C | +3.6 °C | 97 mm | +17 mm |
| May | 16.2 °C | +2.6 °C | 68 mm | -18 mm |
| Jun | 16.6 °C | +0.8 °C | 128 mm | +40 mm |
| Jul | 18.3 °C | +1.4 °C | 79 mm | -17 mm |
| Aug | 18.8 °C | +1.8 °C | 82 mm | -23 mm |
| Sep | 15.1 °C | -0.2 °C | 129 mm | +30 mm |
| Oct | 12.5 °C | 0.0 °C | 146 mm | +39 mm |
| Nov | 9.9 °C | +0.7 °C | 143 mm | +39 mm |
| Dec | 8.4 °C | +0.9 °C | 88 mm | -22 mm |
The year's extremes
What was the weather like that day?
Your birthday, a wedding, a memorable trip: discover the actual weather for any date since 1940.
Frequently asked questions
What is the climate of Letterkenny?
Letterkenny has a temperate oceanic climate (Köppen Cfb). Over 1940-2025, the average annual temperature is 9.3 °C and it receives 1,142 mm of precipitation per year.
What is the hottest day ever recorded in Letterkenny?
The hottest day measured in Letterkenny between 1940 and 2025 was 19 July 2006, reaching 28.8 °C.
What is the coldest day in Letterkenny?
The coldest day measured in Letterkenny between 1940 and 2025 was 1 March 1947, at -12.7 °C.
Does it snow in Letterkenny?
Yes. Letterkenny gets on average 21.8 cm of snow per year and has around 19 frost days.
Has the climate of Letterkenny warmed?
Yes: Letterkenny warmed by +0.9 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Letterkenny?
The wettest day measured in Letterkenny between 1940 and 2025 was 5 December 2015, with 50 mm of rain in 24 hours.
What was the windiest day in Letterkenny?
The windiest day measured in Letterkenny between 1940 and 2025 was 26 December 1998, with winds reaching 71.5 km/h.
What is the warmest month in Letterkenny?
The warmest month in Letterkenny is July (14.2 °C on average); the coldest is January (4.7 °C).
How much does it rain in Letterkenny?
Letterkenny receives on average 1,142 mm of precipitation per year, spread over about 208 rainy days.
Is it sunny in Letterkenny?
Letterkenny gets on average 7.1 hours of sunshine per day, roughly 2,592 hours per year over 1940-2025.
What is the biggest single-day snowfall in Letterkenny?
The heaviest 24-hour snowfall measured in Letterkenny between 1940 and 2025 was 30 March 2010, with 21.8 cm.
Are there tropical nights in Letterkenny?
Almost never: tropical nights (temperature staying above 20 °C) are virtually non-existent in Letterkenny.
What was the most extreme apparent temperature in Letterkenny?
In Letterkenny, between 1940 and 2025, the highest apparent temperature reached 32.7 °C on 29 July 1948, and the lowest was -17.3 °C on 1 March 1947.
Compare Letterkenny with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Letterkenny