Belfast weather in May
Temperature, sea and sunshine in May: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in May
Fair
Best time to visit: June – August
What is the weather like in Belfast in May?
In May, Belfast is cool: daytime highs average 13 °C, and nights cool down to about 9 °C. The sea averages 9.4 °C – swimming is only for the hardy. Expect around 6 hours of sunshine a day. It rains often – on about 14 days, adding up to 70 mm. All in all, May is a so-so month for a holiday in Belfast.
May compared
How the weather changes from April to June. Tap a month to open it.
More details for May
- Daylight
- 16 h 1 min05:19 – 21:20
- UV index
- 6 · highclear sky, noon (estimate)All months
- Muggy days
- 0 daysdew point 18 °C or moreAll months
- Wind
- 22 km/haverage daily peakAll months
- Cloud cover
- 67 %on averageAll months
- Hot days
- 0 days30 °C or more
- Snow days
- 0 days1 cm or more of fresh snow
- Time zone
- UTC+1Europe/London
How the score comes together
- Temperatureweight 50 %49 %
- Sunshineweight 20 %57 %
- Few rainy daysweight 30 %29 %
Each factor is rated from 0 to 100 % and weighted for the travel style “City break”.
What to pack in May
- Sunscreen
- A jumper for the evenings
- Rain jacket or umbrella
Belfast in May: quick answers
Is Belfast hot in May?
No. In May, Belfast is cool: daytime highs average 13 °C and nights drop to about 9 °C.
Can you swim in Belfast in May?
Only if you don't mind cold water: in May the sea averages just 9.4 °C. Comfortable swimming temperatures are not reached at any time of year.
Does it rain much in Belfast in May?
It rains often – on about 14 days, adding up to 70 mm.
Belfast month by month
The whole year in BelfastAll destinations: United KingdomWhere to go in MaySea temperature in May
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences