Castlebar climate — normals and trends
Castlebar (Ireland) has a temperate oceanic climate (Cfb) under the Köppen-Geiger classification. Its mean annual temperature is 9.6 °C and it receives 1,074 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 (14.6 °C on average) and the coldest is January (5.1 °C). Rainfall peaks in December.
Castlebar averages 22 frost days, 0 hot days (≥ 30 °C) and 186 rainy days per year.
Castlebar has warmed by +0.4 °C between 1940 and 2025, or +0.05 °C per decade. This trend is statistically significant.
The number of frost days there went from about 28 to 16 per year over the period.
The hottest day of the period reached 28.6 °C (on 29 July 1948) and the coldest -11.7 °C (on 25 December 2010).
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
CastlebarConnacht
- coords
- 53.85°, -9.30°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
9.6°C
Average daily high
12.3°C
Average daily low
6.9°C
Annual rainfall
1,074mm
Sunshine / day
7.3h
Mean relative humidity
84%
Average peak wind
21.4km/h
Seasonal range
9.5°C
Frost days (< 0 °C)
22 d/yr
Hot days (≥ 30 °C)
0 d/yr
Rainy days (≥ 1 mm)
186 d/yr
Annual snowfall
11.7 cm
Average feels-like high
9.6 °C
Average feels-like low
3.9 °C
Average peak gust
45.9 km/h
Tropical nights (≥ 20 °C)
0 d/yr
Solar radiation
9.6 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+0.4 °C
since 1940
+0.1 °C per decade · r² = 0.06 · p = 0.019
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
28.6 °C
29 July 1948
Coldest day
-11.7 °C
25 December 2010
Wettest day
56 mm
27 October 1989
Windiest day
70.9 km/h
26 December 1998
Strongest gust
145.8 km/h
26 December 1998
Hottest feels-like
32.5 °C
13 July 1983
Coldest feels-like
-15.9 °C
25 December 2010
Snowiest day
14.6 cm
16 November 1965
Sunniest day
16.7 h
19 June 2025
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 | 7.3 °C | 0.0 °C | 68 mm | -34 mm |
| Feb | 8.6 °C | +0.8 °C | 128 mm | +46 mm |
| Mar | 11.4 °C | +1.9 °C | 39 mm | -43 mm |
| Apr | 14.7 °C | +3.1 °C | 89 mm | +19 mm |
| May | 17.3 °C | +3.1 °C | 58 mm | -26 mm |
| Jun | 16.9 °C | +0.6 °C | 106 mm | +31 mm |
| Jul | 18.6 °C | +1.1 °C | 72 mm | -7 mm |
| Aug | 19.0 °C | +1.5 °C | 98 mm | +5 mm |
| Sep | 15.2 °C | -0.5 °C | 144 mm | +54 mm |
| Oct | 12.9 °C | 0.0 °C | 115 mm | +9 mm |
| Nov | 10.3 °C | +0.7 °C | 132 mm | +31 mm |
| Dec | 8.6 °C | +0.6 °C | 133 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 Castlebar?
Castlebar has a temperate oceanic climate (Köppen Cfb). Over 1940-2025, the average annual temperature is 9.6 °C and it receives 1,074 mm of precipitation per year.
What is the hottest day ever recorded in Castlebar?
The hottest day measured in Castlebar between 1940 and 2025 was 29 July 1948, reaching 28.6 °C.
What is the coldest day in Castlebar?
The coldest day measured in Castlebar between 1940 and 2025 was 25 December 2010, at -11.7 °C.
Does it snow in Castlebar?
Yes. Castlebar gets on average 11.7 cm of snow per year and has around 22 frost days.
Has the climate of Castlebar warmed?
Yes: Castlebar warmed by +0.4 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Castlebar?
The wettest day measured in Castlebar between 1940 and 2025 was 27 October 1989, with 56 mm of rain in 24 hours.
What was the windiest day in Castlebar?
The windiest day measured in Castlebar between 1940 and 2025 was 26 December 1998, with winds reaching 70.9 km/h.
What is the warmest month in Castlebar?
The warmest month in Castlebar is July (14.6 °C on average); the coldest is January (5.1 °C).
How much does it rain in Castlebar?
Castlebar receives on average 1,074 mm of precipitation per year, spread over about 186 rainy days.
Is it sunny in Castlebar?
Castlebar gets on average 7.3 hours of sunshine per day, roughly 2,665 hours per year over 1940-2025.
What is the biggest single-day snowfall in Castlebar?
The heaviest 24-hour snowfall measured in Castlebar between 1940 and 2025 was 16 November 1965, with 14.6 cm.
Are there tropical nights in Castlebar?
Almost never: tropical nights (temperature staying above 20 °C) are virtually non-existent in Castlebar.
What was the most extreme apparent temperature in Castlebar?
In Castlebar, between 1940 and 2025, the highest apparent temperature reached 32.5 °C on 13 July 1983, and the lowest was -15.9 °C on 25 December 2010.
Compare Castlebar with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Castlebar