August is one of the warmer months of the year in Swansea, with average highs near 18.8°C and lows around 13.8°C (mean 16.3°C). It is about average for rainfall, averaging 83 mm of rainfall and 84% relative humidity across the period.
August is one of the warmer months of the year in Swansea. Across 45 years of records, the warmest August in Swansea was 1995 — when the month averaged 18.6°C — while the coldest was 1986 at 14°C. Typical August days reach 18.8°C with nights near 13.8°C. The long-term trend is warming, about 0.2°C per decade.
August is about average for rainfall in Swansea, averaging 83 mm of rainfall. The wettest August on record was 1992 with 162 mm, while the driest was 1995 at 11 mm.
Relative humidity in Swansea during August averages 84%. The most humid August was 2008 at 88%, and the least humid was 1995 at 79%.
August receives about 4.3 kWh/m²/day of solar energy in Swansea. The sunniest August was 1995 at 5.4 kWh/m²/day, and the cloudiest was 2008 at 3.4.
Average wind speed in Swansea during August is 3.9 m/s. The windiest August was 1985 at 5.4 m/s, while the calmest were 1981, 1984 and 2003 at 2.9 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 15.9°C | 16.4°C | 16.4°C | 16.1°C | 17.1°C | +1.2°C |
| Avg High | 18.4°C | 19.0°C | 18.8°C | 18.4°C | 19.7°C | +1.3°C |
| Avg Low | 13.3°C | 13.7°C | 13.9°C | 13.8°C | 14.5°C | +1.2°C |
| Avg Rain | 71 mm | 82 mm | 78 mm | 105 mm | 72 mm | +0 mm |
August temperatures in Swansea have risen by about 0.7°C between 1981–1985 and 2021–2025.
August has ranged from a record low of 9°C (1986) to a record high of 27.8°C (1990).
Rainfall in August is about average for rainfall, averaging 83 mm, with a wettest year of 162 mm.
One of the best times to visit Swansea
August is one of the best times to visit Swansea. Expect days averaging 18.8°C and nights around 13.8°C (mean 16.3°C) — warmer than Swansea's yearly average — with higher rainfall (83 mm), so conditions are generally comfortable for sightseeing and outdoor plans.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 20.4°C | 17.7°C | 14.9°C | 27.4°C | 12.6°C | 50 mm | 82% | 3.9 m/s | 4.6 |
| 2024 | 19.1°C | 16.8°C | 14.4°C | 24.0°C | 12.4°C | 67 mm | 85% | 4.4 m/s | 4 |
| 2023 | 19.0°C | 16.6°C | 14.1°C | 22.3°C | 12.3°C | 86 mm | 86% | 4.1 m/s | 3.9 |
| 2022 | 21.2°C | 18.2°C | 15.1°C | 26.8°C | 11.9°C | 35 mm | 80% | 3.3 m/s | 5 |
| 2021 | 18.8°C | 16.2°C | 13.7°C | 20.9°C | 11.4°C | 58 mm | 86% | 3.9 m/s | 4 |
| 2020 | 19.6°C | 17.3°C | 14.9°C | 26.6°C | 10.3°C | 132 mm | 85% | 4 m/s | 3.9 |
| 2019 | 19.2°C | 16.9°C | 14.6°C | 23.4°C | 12.1°C | 109 mm | 85% | 4.5 m/s | 4.5 |
| 2018 | 19.0°C | 16.7°C | 14.3°C | 23.1°C | 11.0°C | 101 mm | 84% | 3.8 m/s | 4.1 |
| 2017 | 18.1°C | 15.8°C | 13.6°C | 21.4°C | 11.4°C | 84 mm | 84% | 4 m/s | 4.3 |
| 2016 | 19.1°C | 16.6°C | 14.1°C | 22.8°C | 11.5°C | 98 mm | 86% | 4.2 m/s | 4.4 |
| 2015 | 18.1°C | 15.6°C | 13.2°C | 21.1°C | 11.5°C | 158 mm | 85% | 4 m/s | 3.7 |
| 2014 | 17.5°C | 15.3°C | 13.2°C | 20.1°C | 10.5°C | 120 mm | 82% | 4.6 m/s | 4.3 |
| 2013 | 19.2°C | 16.6°C | 14.1°C | 22.9°C | 11.4°C | 93 mm | 85% | 3.8 m/s | 4.3 |
| 2012 | 18.5°C | 16.3°C | 14.1°C | 22.1°C | 10.3°C | 119 mm | 87% | 4.2 m/s | 3.9 |
| 2011 | 17.4°C | 15.2°C | 13.1°C | 20.0°C | 11.3°C | 75 mm | 84% | 3.8 m/s | 4 |
| 2010 | 18.1°C | 15.7°C | 13.3°C | 20.8°C | 10.0°C | 95 mm | 84% | 4.3 m/s | 4 |
| 2009 | 18.5°C | 16.3°C | 14.0°C | 21.2°C | 12.1°C | 64 mm | 86% | 4.3 m/s | 4 |
| 2008 | 18.0°C | 16.1°C | 14.2°C | 21.1°C | 11.5°C | 145 mm | 88% | 4.8 m/s | 3.4 |
| 2007 | 18.5°C | 15.8°C | 13.0°C | 21.4°C | 10.9°C | 73 mm | 84% | 4 m/s | 4.7 |
| 2006 | 18.3°C | 16.1°C | 13.9°C | 22.0°C | 12.0°C | 54 mm | 85% | 4.3 m/s | 4.2 |
| 2005 | 18.8°C | 16.1°C | 13.3°C | 22.0°C | 11.0°C | 56 mm | 85% | 3.6 m/s | 4.9 |
| 2004 | 19.2°C | 16.8°C | 14.4°C | 23.3°C | 11.5°C | 127 mm | 86% | 3.7 m/s | 4.3 |
| 2003 | 20.6°C | 17.6°C | 14.6°C | 26.0°C | 10.9°C | 29 mm | 83% | 2.9 m/s | 4.6 |
| 2002 | 18.8°C | 16.1°C | 13.4°C | 20.3°C | 11.7°C | 46 mm | 86% | 3 m/s | 4.1 |
| 2001 | 18.7°C | 16.4°C | 14.0°C | 22.0°C | 11.6°C | 100 mm | 86% | 3.6 m/s | 3.9 |
| 2000 | 18.9°C | 16.5°C | 14.1°C | 22.4°C | 12.0°C | 83 mm | 85% | 3.6 m/s | 4.3 |
| 1999 | 18.8°C | 16.4°C | 14.1°C | 22.6°C | 11.6°C | 145 mm | 86% | 3.3 m/s | 4.1 |
| 1998 | 18.4°C | 15.7°C | 12.9°C | 23.4°C | 10.7°C | 56 mm | 85% | 3.9 m/s | 4.8 |
| 1997 | 20.4°C | 17.9°C | 15.5°C | 24.1°C | 13.3°C | 152 mm | 87% | 3.2 m/s | 4 |
| 1996 | 18.5°C | 15.7°C | 13.0°C | 22.1°C | 10.8°C | 81 mm | 85% | 3.8 m/s | 4.5 |
| 1995 🔥 | 22.0°C | 18.6°C | 15.2°C | 27.1°C | 11.8°C | 11 mm | 79% | 3.2 m/s | 5.4 |
| 1994 | 18.2°C | 15.8°C | 13.3°C | 21.3°C | 10.3°C | 90 mm | 83% | 4.1 m/s | 4.4 |
| 1993 | 17.5°C | 14.9°C | 12.3°C | 19.6°C | 9.7°C | 49 mm | 83% | 3.6 m/s | 4.4 |
| 1992 🌧️ | 17.6°C | 15.4°C | 13.2°C | 19.8°C | 10.7°C | 162 mm | 84% | 4.7 m/s | 4 |
| 1991 | 19.1°C | 16.2°C | 13.2°C | 22.7°C | 11.0°C | 27 mm | 85% | 3.4 m/s | 4.7 |
| 1990 | 19.9°C | 17.2°C | 14.5°C | 27.8°C | 12.3°C | 52 mm | 84% | 3.7 m/s | 4.5 |
| 1989 | 18.9°C | 16.4°C | 13.8°C | 21.2°C | 11.0°C | 51 mm | 83% | 4.2 m/s | 4.7 |
| 1988 | 17.3°C | 14.9°C | 12.4°C | 23.4°C | 10.1°C | 95 mm | 85% | 4.2 m/s | 4.1 |
| 1987 | 18.3°C | 15.7°C | 13.2°C | 22.5°C | 9.6°C | 35 mm | 85% | 3.5 m/s | 4.1 |
| 1986 ❄️ | 16.3°C | 14.0°C | 11.6°C | 19.4°C | 9.0°C | 117 mm | 82% | 4.1 m/s | 3.5 |
| 1985 | 16.6°C | 14.7°C | 12.7°C | 20.7°C | 10.2°C | 150 mm | 86% | 5.4 m/s | 3.9 |
| 1984 | 20.3°C | 17.5°C | 14.7°C | 24.4°C | 11.7°C | 50 mm | 83% | 2.9 m/s | 4.6 |
| 1983 | 20.3°C | 17.2°C | 14.0°C | 24.5°C | 10.7°C | 33 mm | 83% | 3.1 m/s | — |
| 1982 | 18.1°C | 15.8°C | 13.5°C | 23.8°C | 10.9°C | 75 mm | 84% | 4.5 m/s | — |
| 1981 | 19.5°C | 16.6°C | 13.6°C | 22.6°C | 10.7°C | 35 mm | 84% | 2.9 m/s | — |
Actual recorded August data for each year, 1981–2025 — sourced from NASA POWER.
The average high in August is around 18.8°C with lows near 13.8°C (mean 16.3°C), based on 45 years of NASA POWER data.
August averages 83 mm of rainfall in Swansea, about average for rainfall. The wettest on record was 162 mm in 1992.
The hottest August reached 27.8°C in 1990. The coldest dipped to 9°C in 1986.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average August temperatures have risen by about 0.7°C. Daytime highs moved from 19°C to 19.7°C and overnight lows from 13.7°C to 14.4°C over the same span.
August is one of the warmer months of the year in Swansea and about average for rainfall, so plan for around 18.8°C daytime highs and 13.8°C at night.
Not quite — August is the 12th coolest month in Swansea, averaging 16.3°C.
For August in Swansea, pack light layers you can adjust through the day, with typical highs of 18.8°C and lows of 13.8°C. Bring an umbrella or light rain jacket too.
Relative humidity in August averages 84% — quite humid.
Average wind speed in August is 3.9 m/s. The windiest August on record averaged 5.4 m/s (1985).
The wettest August on record was 1992 with 162 mm. On average, August sees 83 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in Swansea behaves each August, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for August specifically, along with year-by-year records and how the month has changed over the decades.
