Belfast weather in May
May in Belfast: cool, a little rain, with clean air — an excellent time to visit.
#4 of 12 months in Belfast · #408 of 897 destinations to visit in May · comfort 83/100 (tier A)
Updated June 2026 · climate normals from ERA5 reanalysis
Traveller notes on Belfast in May
No notes yet. Open Belfast on the map to add the first one.
Belfast climate normals — May
| Daytime high | 14°C / 57°F | 🙂 cool |
|---|---|---|
| Nighttime low | 9°C / 47°F | |
| Rainfall | 63 mm / 2.5 in | 🌦 some rain |
| Rainy days | 14 days | |
| Humidity | 80% | 💦 very humid |
| Dew point | 9°C / 47°F | |
| Sunshine | 10.3 h/day | |
| Daylight | 16.1 h | |
| Wind | 19 km/h / 12 mph | |
| Air quality (US AQI) | 40 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Where is Belfast?
Loading map…
Belfast in May — FAQ
- Is May a good time to visit Belfast?
- May in Belfast: cool, a little rain, with clean air — an excellent time to visit. It ranks #4 of 12 months for Belfast on SeasonMap's comfort score (83/100).
- What is the weather like in Belfast in May?
- In May, Belfast averages a daily high of 13.7°C and a low of 8.6°C, with about 62.6 mm of rain over roughly 14.2 rainy days.
- What is the air quality in Belfast in May?
- Belfast has a mean US Air Quality Index of about 40 in May.