Isle of Arran climate — normals and trends
Isle of Arran (United Kingdom) has a temperate oceanic climate (Cfb) under the Köppen-Geiger classification. Its mean annual temperature is 9.5 °C and it receives 1,371 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 August (13.8 °C on average) and the coldest is February (5.7 °C). Rainfall peaks in December.
Isle of Arran averages 1 frost days, 0 hot days (≥ 30 °C) and 195 rainy days per year.
Isle of Arran has warmed by +0.9 °C between 1940 and 2025, or +0.11 °C per decade. This trend is statistically significant.
The number of frost days there went from about 2 to 0 per year over the period.
The hottest day of the period reached 21.1 °C (on 19 July 2006) and the coldest -2.7 °C (on 12 January 1987).
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
Isle of ArranScotland
- coords
- 55.58°, -5.21°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
9.5°C
Average daily high
10.4°C
Average daily low
8.6°C
Annual rainfall
1,371mm
Sunshine / day
7.7h
Mean relative humidity
82%
Average peak wind
39.9km/h
Seasonal range
8.1°C
Frost days (< 0 °C)
1 d/yr
Hot days (≥ 30 °C)
0 d/yr
Rainy days (≥ 1 mm)
195 d/yr
Annual snowfall
11.2 cm
Average feels-like high
6.2 °C
Average feels-like low
2.6 °C
Average peak gust
54.2 km/h
Tropical nights (≥ 20 °C)
0 d/yr
Solar radiation
9.8 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+0.9 °C
since 1940
+0.1 °C per decade · r² = 0.32 · 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
21.1 °C
19 July 2006
Coldest day
-2.7 °C
12 January 1987
Wettest day
52 mm
21 September 1985
Windiest day
102.9 km/h
26 December 1998
Strongest gust
170.6 km/h
26 December 1998
Hottest feels-like
21.4 °C
22 July 2021
Coldest feels-like
-12.8 °C
14 January 1984
Snowiest day
16.3 cm
29 January 1945
Sunniest day
17.0 h
20 June 1940
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 | 7.7 °C | +0.4 °C | 93 mm | -51 mm |
| Feb | 7.4 °C | +0.7 °C | 83 mm | -24 mm |
| Mar | 8.7 °C | +1.5 °C | 50 mm | -47 mm |
| Apr | 10.2 °C | +1.9 °C | 55 mm | -19 mm |
| May | 12.6 °C | +2.3 °C | 63 mm | -6 mm |
| Jun | 13.8 °C | +1.3 °C | 133 mm | +60 mm |
| Jul | 15.4 °C | +1.4 °C | 75 mm | -13 mm |
| Aug | 16.1 °C | +1.5 °C | 79 mm | -26 mm |
| Sep | 14.5 °C | +0.7 °C | 148 mm | +22 mm |
| Oct | 12.6 °C | +0.4 °C | 224 mm | +65 mm |
| Nov | 10.6 °C | +0.7 °C | 223 mm | +59 mm |
| Dec | 9.4 °C | +1.0 °C | 199 mm | +34 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 Isle of Arran?
Isle of Arran has a temperate oceanic climate (Köppen Cfb). Over 1940-2025, the average annual temperature is 9.5 °C and it receives 1,371 mm of precipitation per year.
What is the hottest day ever recorded in Isle of Arran?
The hottest day measured in Isle of Arran between 1940 and 2025 was 19 July 2006, reaching 21.1 °C.
What is the coldest day in Isle of Arran?
The coldest day measured in Isle of Arran between 1940 and 2025 was 12 January 1987, at -2.7 °C.
Does it snow in Isle of Arran?
Yes. Isle of Arran gets on average 11.2 cm of snow per year and has around 1 frost days.
Has the climate of Isle of Arran warmed?
Yes: Isle of Arran warmed by +0.9 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Isle of Arran?
The wettest day measured in Isle of Arran between 1940 and 2025 was 21 September 1985, with 52 mm of rain in 24 hours.
What was the windiest day in Isle of Arran?
The windiest day measured in Isle of Arran between 1940 and 2025 was 26 December 1998, with winds reaching 102.9 km/h.
What is the warmest month in Isle of Arran?
The warmest month in Isle of Arran is August (13.8 °C on average); the coldest is February (5.7 °C).
How much does it rain in Isle of Arran?
Isle of Arran receives on average 1,371 mm of precipitation per year, spread over about 195 rainy days.
Is it sunny in Isle of Arran?
Isle of Arran gets on average 7.7 hours of sunshine per day, roughly 2,811 hours per year over 1940-2025.
What is the biggest single-day snowfall in Isle of Arran?
The heaviest 24-hour snowfall measured in Isle of Arran between 1940 and 2025 was 29 January 1945, with 16.3 cm.
Are there tropical nights in Isle of Arran?
Almost never: tropical nights (temperature staying above 20 °C) are virtually non-existent in Isle of Arran.
What was the most extreme apparent temperature in Isle of Arran?
In Isle of Arran, between 1940 and 2025, the highest apparent temperature reached 21.4 °C on 22 July 2021, and the lowest was -12.8 °C on 14 January 1984.
Compare Isle of Arran with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Isle of Arran