Cardiff weather in May
May in Cardiff: cool, a little rain, with clean air — an excellent time to visit.
#4 of 12 months in Cardiff · #376 of 897 destinations to visit in May · comfort 84/100 (tier A)
Updated June 2026 · climate normals from ERA5 reanalysis
Traveller notes on Cardiff in May
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Cardiff climate normals — May
| Daytime high | 16°C / 60°F | 🙂 cool |
|---|---|---|
| Nighttime low | 9°C / 47°F | |
| Rainfall | 67 mm / 2.6 in | 🌦 some rain |
| Rainy days | 11 days | |
| Humidity | 79% | 💦 very humid |
| Dew point | 9°C / 48°F | |
| Sunshine | 11.1 h/day | |
| Daylight | 15.6 h | |
| Wind | 21 km/h / 13 mph | |
| Air quality (US AQI) | 41 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
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Cardiff in May — FAQ
- Is May a good time to visit Cardiff?
- May in Cardiff: cool, a little rain, with clean air — an excellent time to visit. It ranks #4 of 12 months for Cardiff on SeasonMap's comfort score (84/100).
- What is the weather like in Cardiff in May?
- In May, Cardiff averages a daily high of 15.5°C and a low of 8.5°C, with about 66.8 mm of rain over roughly 11.4 rainy days.
- What is the air quality in Cardiff in May?
- Cardiff has a mean US Air Quality Index of about 41 in May.