Swansea Weather in September
What's the weather like in Swansea (Wales) in September 2025?
The climate in Swansea during September can be summarized as mild and damp.
September is in the fall / autumn in Swansea and is typically the 4th warmest month of the year. Daytime maximum temperatures average around 17°C (63°F), whilst at night 11°C (52°F) is normal.
| Daytime temperature | 17.4°C 63.2°F |
|---|---|
| Nightly temperature | 11.3°C 52.3°F |
| Average temperature | 14.3°C 57.7°F |
| Daily sunshine | 5 hrs |
| Avg rainfall | 111 mm 4.4 ins |
| Rainy days | 16 days |
| Sea temperature | 16.1°C 60.9°F |
| Humidity | 86% |
| Windspeed | 17.6kph 11 mph |
On average September is the 5th wettest month of the year in Swansea with around 111mm 4.4 inches of rain making it a damp time to visit. This rainfall is typically spread over 16 days, although this may vary considerably.
On the flip side this corresponds to an average of 5 hours of sunshine per day.
September temperatures in Swansea
September rainfall
September hourly sunshine
The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in Swansea in September 2025.
Other monthly averages
Best places to visit in September
Swansea weather stats
| Hottest month: | July | 19.5°C 67.1°F |
|---|---|---|
| Driest month: | April | 69mm 2.7ins |
| Sunniest month: | May | 7hrs |
| Coldest month: | February | 7.2°C 45°F |
| Wettest month: | December | 140mm 5.5ins |
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