Belfast weather in December 2025

Q: How warm is it in Belfast in December?

Daytime temperatures usually reach 8°C in Belfast in December, falling to 2°C at night.

Q: How sunny is it in Belfast in December?

There are normally 1 hour of bright sunshine each day in Belfast in December - that's 18% of daylight hours.

Q: Is the sea cold around Belfast in December?

The average sea temperature around Belfast in December is 10°C.

Q: Does it rain in Belfast in December?

There are usually 20 days with some rain in Belfast in December and the average monthly rainfall is 94mm.

Expect daytime maximum temperatures of 8°C in Belfast, Northern Ireland in December based on long-term weather averages. There is 1 hour of sunshine per day on average with 20 days with some rainfall and typically 94 mm of rainfall in the month.

8
8°C max day temperature
1
1 hour of sunshine per day
20
20 days with some rainfall
2
2°C min night temperature
7
7 hours of daylight per day
0
No heat & humidity
94
94 mm of monthly rainfall
0
No UV (Maximum) Index UV index
10
10°C sea temperature

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The December weather guide for Northern Ireland (Belfast) shows long term weather averages processed from data supplied by CRU (University of East Anglia), the Met Office & the Netherlands Meteorological Institute. Find out more about our data sources.

Metric (°C / mm) | Imperial (°F / inches)