Climate averages 1991–2020

Swansea weather
in August.

A mild, wet month: one of the warmest and the 8th driest of the year.

Long-term climate patterns, not a forecast for a particular trip.

Average high 18.5°C Daytime mean, August

Average low 13.8°C Night-time mean, August

Rainfall 101 mm 14 days with ≥1 mm

Daylight 15 h Sunrise to sunset, per day

August is a mild month in Swansea: daytime highs average 18.5°C and nights cool to about 13.8°C. By daytime temperature it is one of the warmest months of the year.

Expect about 101 mm of rain on roughly 14 days, which makes August a wet month (the 8th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 14 h 37 min on an average August day.

The nearest other city in this atlas is Cardiff (55 km away). In August its highs average 19.2°C, 0.7°C warmer than Swansea, with 87 mm of rain.

Among the 143 cities listed in the United Kingdom, Swansea ranks joint 118th of 143 for the warmest August highs and joint 134th of 143 for the driest August (rainfall, lowest first). The mean August high of those 143 cities is 19.7°C; Swansea is 1.2°C cooler than that mean.

From August to September, average highs fall by 1.7°C to 16.8°C, and monthly rainfall falls from 101 mm to 96 mm.

The annual picture

August in context

30-year average

Average highAverage low°C

Monthly rainfall

Average total · mm

Averages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated

Every month, side by side

Swansea climate table

1991–2020

Monthly climate averages for Swansea, 1991–2020
Month	Average highHigh / low	Average low	Rainfall mm/month	Rain days ≥1 mm/day	Daylight hours/dayDaylight h/day
January	7.7°C4.0°C	4.0°C	128	17.0	8.48 h
February	7.8°C3.7°C	3.7°C	92	13.1	9.910 h
March	9.4°C4.5°C	4.5°C	83	13.7	11.812 h
April	11.8°C6.1°C	6.1°C	69	12.0	13.814 h
May	14.6°C8.8°C	8.8°C	72	12.4	15.616 h
June	16.9°C11.6°C	11.6°C	79	12.2	16.617 h
July	18.5°C13.5°C	13.5°C	86	13.8	16.216 h
August, selected	18.5°C13.8°C	13.8°C	101	14.3	14.615 h
September	16.8°C12.1°C	12.1°C	96	13.2	12.713 h
October	13.7°C9.7°C	9.7°C	143	16.7	10.711 h
November	10.5°C6.9°C	6.9°C	143	17.3	8.99 h
December	8.2°C4.7°C	4.7°C	145	16.8	7.98 h

Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.

Compare places

August in nearby cities

Distance from Swansea

Read the numbers correctly

Climate, not a promise.

These patterns help compare months. They cannot tell you the weather on a specific day of your trip.

Sources, method and limits

How these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Swansea) is explained once on the Swansea year overview and on the Sources, method and limits page.