Swansea climate — normals and trends
Swansea (United Kingdom) has a temperate oceanic climate (Cfb) under the Köppen-Geiger classification. Its mean annual temperature is 10.7 °C and it receives 1,163 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 (16.1 °C on average) and the coldest is February (5.8 °C). Rainfall peaks in December.
Swansea averages 6 frost days, 0 hot days (≥ 30 °C) and 172 rainy days per year.
Swansea has warmed by +1.3 °C between 1940 and 2025, or +0.15 °C per decade. This trend is statistically significant.
The number of frost days there went from about 11 to 1 per year over the period.
The hottest day of the period reached 27.2 °C (on 18 July 2022) and the coldest -8.2 °C (on 21 January 1940).
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
SwanseaWales
- coords
- 51.62°, -3.94°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
10.7°C
Average daily high
12.3°C
Average daily low
9.0°C
Annual rainfall
1,163mm
Sunshine / day
8.2h
Mean relative humidity
81%
Average peak wind
29.0km/h
Seasonal range
10.3°C
Frost days (< 0 °C)
6 d/yr
Hot days (≥ 30 °C)
0 d/yr
Rainy days (≥ 1 mm)
172 d/yr
Annual snowfall
6.8 cm
Average feels-like high
9.2 °C
Average feels-like low
5.0 °C
Average peak gust
44.6 km/h
Tropical nights (≥ 20 °C)
0 d/yr
Solar radiation
11.2 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.3 °C
since 1940
+0.2 °C per decade · r² = 0.35 · 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
27.2 °C
18 July 2022
Coldest day
-8.2 °C
21 January 1940
Wettest day
63 mm
20 October 1944
Windiest day
83.7 km/h
30 November 1954
Strongest gust
153.4 km/h
25 January 1990
Hottest feels-like
29.0 °C
12 July 2025
Coldest feels-like
-14.9 °C
13 January 1987
Snowiest day
20.7 cm
8 January 1982
Sunniest day
16.0 h
26 June 2018
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 | 7.6 °C | +0.1 °C | 134 mm | +17 mm |
| Feb | 7.9 °C | +0.6 °C | 99 mm | +12 mm |
| Mar | 10.4 °C | +1.8 °C | 22 mm | -60 mm |
| Apr | 13.2 °C | +2.7 °C | 90 mm | +26 mm |
| May | 15.6 °C | +2.5 °C | 47 mm | -25 mm |
| Jun | 17.0 °C | +1.4 °C | 107 mm | +37 mm |
| Jul | 19.1 °C | +1.8 °C | 57 mm | -19 mm |
| Aug | 19.7 °C | +2.0 °C | 76 mm | -17 mm |
| Sep | 16.4 °C | 0.0 °C | 220 mm | +115 mm |
| Oct | 14.2 °C | +0.4 °C | 146 mm | +13 mm |
| Nov | 11.9 °C | +1.3 °C | 252 mm | +122 mm |
| Dec | 9.8 °C | +1.2 °C | 228 mm | +94 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 Swansea?
Swansea has a temperate oceanic climate (Köppen Cfb). Over 1940-2025, the average annual temperature is 10.7 °C and it receives 1,163 mm of precipitation per year.
What is the hottest day ever recorded in Swansea?
The hottest day measured in Swansea between 1940 and 2025 was 18 July 2022, reaching 27.2 °C.
What is the coldest day in Swansea?
The coldest day measured in Swansea between 1940 and 2025 was 21 January 1940, at -8.2 °C.
Does it snow in Swansea?
Yes. Swansea gets on average 6.8 cm of snow per year and has around 6 frost days.
Has the climate of Swansea warmed?
Yes: Swansea warmed by +1.3 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Swansea?
The wettest day measured in Swansea between 1940 and 2025 was 20 October 1944, with 63 mm of rain in 24 hours.
What was the windiest day in Swansea?
The windiest day measured in Swansea between 1940 and 2025 was 30 November 1954, with winds reaching 83.7 km/h.
What is the warmest month in Swansea?
The warmest month in Swansea is August (16.1 °C on average); the coldest is February (5.8 °C).
How much does it rain in Swansea?
Swansea receives on average 1,163 mm of precipitation per year, spread over about 172 rainy days.
Is it sunny in Swansea?
Swansea gets on average 8.2 hours of sunshine per day, roughly 2,993 hours per year over 1940-2025.
What is the biggest single-day snowfall in Swansea?
The heaviest 24-hour snowfall measured in Swansea between 1940 and 2025 was 8 January 1982, with 20.7 cm.
Are there tropical nights in Swansea?
Almost never: tropical nights (temperature staying above 20 °C) are virtually non-existent in Swansea.
What was the most extreme apparent temperature in Swansea?
In Swansea, between 1940 and 2025, the highest apparent temperature reached 29.0 °C on 12 July 2025, and the lowest was -14.9 °C on 13 January 1987.
Compare Swansea with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Swansea