Climate Insights for Belfast

The climate in Belfast is temperate. The average annual temperature is 10°C and approximately 983mm of precipitation falls per year. Belfast receives a notable amount of rainfall throughout the year, including during its driest month. Belfast is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: August, July, June. The coldest months are February, January, March, when temperatures can drop to 5°C.

Belfast sees moderate temperature variation throughout the year, ranging from 5°C to 17°C. August is the warmest month, though highs remain moderate at 17°C with a mean of 15°C. February is the coolest month, with minimum temperatures around 5°C and an average of 6°C. Daily temperature variation is modest, with an average difference of 4°C between highs and lows. The sharpest temperature change occurs between April and May, with a 3°C shift in average temperatures.

Belfast is a moderately rainy area, receiving approximately 983mm of precipitation annually, which averages out to around 82mm per month. The wettest month is December, averaging 104mm of rainfall. August and October also tend to see above-average precipitation. The driest month is April, with just 55mm. That's 49mm less than December, the wettest month. Rainfall is relatively evenly distributed throughout the year, so there is no pronounced dry or wet season to plan around.

Belfast is moderately windy, with an average annual wind speed of 25km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is February, averaging 31km/h, which can feel quite blustery and may affect outdoor activities. The calmest conditions occur in July, with average winds dropping to 20km/h, making it an ideal period for wind-sensitive activities. There is moderate seasonal variation in wind speed, with a 11km/h gap between the calmest and windiest months. Wind tends to be stronger during winter months, driven by seasonal pressure systems. The seasonal averages break down to 30km/h in winter, 24km/h in spring, 21km/h in summer, 26km/h in autumn.

It is currently spring in Belfast, which began on March 20, 2026. Belfast is in the Northern Hemisphere, where spring begins in March, summer in June, autumn in September, and winter in December. The warmest period peaks in August at around 17°C, while the coldest stretch bottoms out in February near 5°C. Summer is next, beginning on June 21, 2026 — 89 days from now.

The best time to visit Belfast is during August, when the weather is most comfortable for travellers. During these months, average temperatures hover around 15°C with modest rainfall averaging 98mm per month. By contrast, February can be quite cold with temperatures dropping to 5°C. Despite being the best months overall, some rain is still likely — pack a waterproof layer and plan a mix of indoor and outdoor activities.

The table below shows monthly climate averages for Belfast based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.