Climate averages 1991–2020
Belfast weather
in December.
A cold, moderately wet month: the 10th warmest and the 10th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
December is a cold month in Belfast: daytime highs average 7.9°C and nights cool to about 4.4°C. By daytime temperature it is the 10th warmest of the 12 months.
Expect about 82 mm of rain on roughly 14 days, which makes December a moderately wet month (the 10th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 7 h 23 min on an average December day.
The nearest other city in this atlas is Lisburn (11 km away). In December its highs average 7.5°C, about as warm as Belfast, with 82 mm of rain.
Among the 143 cities listed in the United Kingdom, Belfast ranks joint 14th of 143 for the warmest December highs and joint 106th of 143 for the driest December (rainfall, lowest first). The mean December high of those 143 cities is 7.2°C; Belfast is 0.8°C warmer than that mean.
From December to January, average highs fall by 0.5°C to 7.5°C, and monthly rainfall falls from 82 mm to 77 mm.
The annual picture
December in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Belfast climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 7.5°C3.9°C | 3.9°C | 77 | 14.2 | 7.98 h |
| February | 7.7°C3.8°C | 3.8°C | 63 | 12.2 | 9.710 h |
| March | 9.1°C4.4°C | 4.4°C | 62 | 13.4 | 11.812 h |
| April | 10.9°C5.9°C | 5.9°C | 65 | 13.0 | 14.014 h |
| May | 13.6°C8.2°C | 8.2°C | 70 | 14.1 | 16.016 h |
| June | 15.9°C10.9°C | 10.9°C | 75 | 13.2 | 17.217 h |
| July | 17.4°C12.5°C | 12.5°C | 81 | 14.6 | 16.717 h |
| August | 17.3°C12.6°C | 12.6°C | 81 | 14.2 | 14.915 h |
| September | 15.7°C11.3°C | 11.3°C | 70 | 12.5 | 12.813 h |
| October | 12.8°C9.0°C | 9.0°C | 86 | 13.5 | 10.611 h |
| November | 9.8°C6.4°C | 6.4°C | 85 | 14.0 | 8.59 h |
| December, selected | 7.9°C4.4°C | 4.4°C | 82 | 13.5 | 7.47 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
December in nearby cities
- Lisburn in DecemberUnited Kingdom · 11 kmHigh 7.5°C · Low 3.6°C · 82 mm rain
- Derry in DecemberUnited Kingdom · 99 kmHigh 7.4°C · Low 3.4°C · 90 mm rain
- Douglas in DecemberIsle of Man · 106 kmHigh 8.9°C · Low 6.6°C · 114 mm rain
- Dublin in DecemberIreland · 142 kmHigh 8.1°C · Low 4.0°C · 76 mm rain
- Tallaght in DecemberIreland · 149 kmHigh 7.6°C · Low 3.4°C · 76 mm rain
- Paisley in DecemberUnited Kingdom · 167 kmHigh 6.2°C · Low 1.8°C · 124 mm rain
- East Kilbride in DecemberUnited Kingdom · 171 kmHigh 5.3°C · Low 0.7°C · 115 mm rain
- Glasgow in DecemberUnited Kingdom · 176 kmHigh 5.9°C · Low 1.4°C · 115 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Belfast) is explained once on the Belfast year overview and on the Sources, method and limits page.
Lisburn lies in the same rainfall cell, so its rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.