Swansea has a temperate climate with warm summers and mild winters.
Temperatures peak in August and drop to their lowest in February, while rainfall is highest during winter months.
Humidity remains high throughout the year, especially during winter months, creating cold and damp conditions.
| Month | 🌤️ | Avg High | Avg Temp | Avg Low | Record High | Record Low | Humid % | Rain (mm) | Wind (m/s) | Solar (kWh/m²) |
|---|---|---|---|---|---|---|---|---|---|---|
| January | ☔ | 7.5°C | 5.8°C | 4.1°C | 12.3°C | -6.6°C | 90% | 110 | 5.3 | 0.81 |
| February | ☔ | 7.5°C | 5.6°C | 3.8°C | 13.2°C | -6.5°C | 90% | 82 | 5.2 | 1.49 |
| March | ☔ | 9.1°C | 6.8°C | 4.6°C | 16.4°C | -4.4°C | 88% | 80 | 4.7 | 2.53 |
| April | 🌨️ | 11.4°C | 8.6°C | 5.8°C | 20.4°C | -0.7°C | 85% | 64 | 4.0 | 3.97 |
| May | 🌤️ | 14.4°C | 11.5°C | 8.6°C | 23.4°C | 2.4°C | 83% | 67 | 3.8 | 5.00 |
| June | 🌤️ | 17.0°C | 14.2°C | 11.4°C | 25.5°C | 6.1°C | 83% | 71 | 3.7 | 5.31 |
| July | ☀️ | 18.8°C | 16.1°C | 13.5°C | 27.3°C | 9.1°C | 84% | 74 | 3.7 | 5.12 |
| August | ☔ | 18.8°C | 16.3°C | 13.8°C | 27.8°C | 9.0°C | 84% | 83 | 3.9 | 4.25 |
| September | ☔ | 17.2°C | 14.7°C | 12.3°C | 25.0°C | 6.1°C | 85% | 87 | 4.2 | 3.16 |
| October | ☔ | 14.1°C | 12.1°C | 10.0°C | 21.5°C | 2.3°C | 87% | 120 | 4.8 | 1.81 |
| November | ☔ | 10.7°C | 8.9°C | 7.2°C | 16.6°C | -1.0°C | 89% | 115 | 4.9 | 0.97 |
| December | ☔ | 8.4°C | 6.8°C | 5.2°C | 14.1°C | -3.0°C | 91% | 124 | 5.3 | 0.60 |
Showing average climate conditions across 45 years (1981–2025)
🧥 Light layers are sufficient — this Mild Winter stays cool without prolonged hard freezes.
🌤️ Conditions are ideal for outdoor activities throughout the day in this Mild Summer.
☔ Moderate Rainfall expected — carry rain gear and plan outdoor activities around these months.
Monthly averages · 1981–2025 climate normals · °C
Temperatures rise steadily from spring, peak in August, and gradually decline through autumn into winter.
These seasonal patterns offer comfortable conditions year-round, with warm summers and mild winters.
Monthly rainfall · 1981–2025 seasonal trends · mm/month
Rainfall is concentrated in the winter months. Humidity stays high (around 87%), peaking during winter months, which creates cold and damp conditions.
☔ Moderate Rainfall expected — carry rain gear and plan outdoor activities around these months.
Monthly averages · 1981–2025
Across 45 years of records, Swansea's temperature shows a slight warming trend over the past decade. Its hottest day reached 27.8°C in August 1990, and its coldest dropped to -6.6°C in January 1987. 2023 was the warmest year overall and 1986 the coolest.
The warmest year in Swansea's recorded history was 2023 (avg: 11.7°C), while the coldest was 1986 (avg: 9.1°C).
Average annual high/low · Last 30 years · °C
Total annual precipitation · Last 30 years · mm/year
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall (mm) | Avg Humidity | Avg Wind |
|---|---|---|---|---|---|---|---|---|
2025 | 14.0°C | 11.6°C | 9.2°C | 27.4°C | 0.0°C | 1129 | 86% | 4.3 m/s |
2024 | 13.5°C | 11.4°C | 9.2°C | 24.0°C | -0.2°C | 1287 | 88% | 4.3 m/s |
2023 | 13.9°C | 11.7°C | 9.4°C | 25.0°C | 0.2°C | 1289 | 87% | 4.4 m/s |
2022 🔥 | 14.1°C | 11.6°C | 9.2°C | 26.9°C | -0.8°C | 990 | 86% | 4.2 m/s |
2021 | 13.2°C | 10.9°C | 8.6°C | 26.2°C | -1.6°C | 1210 | 87% | 4.2 m/s |
2020 🌧️ | 13.5°C | 11.2°C | 8.8°C | 26.6°C | 1.3°C | 1469 | 86% | 4.8 m/s |
2019 | 13.2°C | 11.0°C | 8.7°C | 24.7°C | 0.9°C | 1363 | 87% | 4.3 m/s |
2018 | 13.3°C | 11.0°C | 8.6°C | 24.3°C | -4.5°C | 1177 | 87% | 4.4 m/s |
2017 | 13.2°C | 11.0°C | 8.8°C | 25.5°C | -0.2°C | 1112 | 87% | 4.4 m/s |
2016 | 13.0°C | 10.8°C | 8.5°C | 25.1°C | 0.4°C | 1079 | 87% | 4.3 m/s |
Showing 1 to 10 of 45 years
Based on 45 years of data (1981–2025), August is typically the hottest month in Swansea, Wales, with average high temperatures around 18.8°C.
February is the coldest month in Swansea, with average low temperatures around 3.8°C.
December receives the most rainfall with approximately 124 mm, while April is the driest with 64 mm.
The highest recorded temperature was 27.8°C in August 1990. This is part of the historical record spanning 1981–2025.
The lowest recorded temperature was -6.6°C in January 1987.
This page covers 45 years of climate data from 1981 to 2025. As new data is added to the database the page automatically reflects the updated coverage.
Swansea receives the most sunlight in June with an average solar radiation of 5.31 kWh/m²/day. This solar radiation data, sourced from NASA POWER, is useful for solar energy planning and agriculture in Wales.
All climate data is sourced from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite and model data. It provides monthly averages for temperature, precipitation, humidity, wind speed, and solar radiation.
All weather data is sourced from NASA POWER (Prediction of Worldwide Energy Resources), a NASA project providing solar and meteorological data for renewable energy, building efficiency, and agricultural research.
