Belfast weather in December
Temperature, sea and sunshine in December: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in December
Poor
Best time to visit: June – August
What is the weather like in Belfast in December?
In December, Belfast is cold: daytime highs average 8 °C, and nights cool down to about 5 °C. The sea averages 10.7 °C – swimming is only for the hardy. The sun is scarce, with only about 2 hours a day. It rains often – on about 15 days, adding up to 95 mm. It is often windy, with gusts of around 29 km/h. All in all, December is not an ideal month for a holiday in Belfast.
December compared
How the weather changes from November to January. Tap a month to open it.
| NovemberNov | DecemberDec | JanuaryJan | |
|---|---|---|---|
| Score | 16 | 8 | 7 |
| Day | 10° | 8° | 8° |
| Night | 7° | 5° | 5° |
| Sea | 12° | 11° | 9° |
| Sun | 2 h | 2 h | 2 h |
| Rain days | 15 | 15 | 15 |
More details for December
- Daylight
- 7 h 18 min08:40 – 15:58
- UV index
- 0 · lowclear sky, noon (estimate)All months
- Muggy days
- 0 daysdew point 18 °C or moreAll months
- Wind
- 29 km/haverage daily peakAll months
- Cloud cover
- 74 %on averageAll months
- Hot days
- 0 days30 °C or more
- Snow days
- 0 days1 cm or more of fresh snow
- Time zone
- UTC+0Europe/London
How the score comes together
- Temperatureweight 50 %4 %
- Sunshineweight 20 %0 %
- Few rainy daysweight 30 %19 %
Each factor is rated from 0 to 100 % and weighted for the travel style “City break”.
What to pack in December
- Warm jacket
- Rain jacket or umbrella
- Windproof jacket
Belfast in December: quick answers
Is Belfast hot in December?
No. In December, Belfast is cold: daytime highs average 8 °C and nights drop to about 5 °C.
Can you swim in Belfast in December?
Only if you don't mind cold water: in December the sea averages just 10.7 °C. Comfortable swimming temperatures are not reached at any time of year.
Does it rain much in Belfast in December?
It rains often – on about 15 days, adding up to 95 mm.
Belfast month by month
The whole year in BelfastAll destinations: United KingdomWhere to go in DecemberSea temperature in December
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