Weather in Belfast in August 2025
- August is usually the hottest month of the year in Belfast;
Average weather
Average temperature in Belfast in August
The expected average maximum temperature in August is +19°C with a maximum of +22°C and a minimum of +10°C.
The average maximum temperature goes down 33% by the end of the month, compared with the beginning of the month, from +19°C to +15°C.
Is Belfast warm or cold in August?
Belfast is typically mild in August.
Maximum temperatures go up compared to the previous month from +18°C to +18°C. The minimum temperature also goes up from +12°C to +12°C.
Pack a light jacket as it will be warm in the day and cool in the evenings.
August is the hottest month in Belfast, here is the comparison with other months:
Water temperature in Belfast in August
Water in Belfast in August is Cold. It varies from +14°C to +15°C, with an average of +14°C. This is almost similar to the air temperature, which averages +18°C.
The water temperature in August is one of the warmest of the entire year:
Can you swim in Belfast in August?
Climate in Belfast in August
| July | August | September | ||||
|---|---|---|---|---|---|---|
| Avg. temperature | ||||||
| +18°C | +18°C | +16°C | ||||
| Min. temperature | ||||||
| +4°C | +3°C | +1°C | ||||
| Max. temperature | ||||||
| +29°C | +29°C | +25°C | ||||
| Rainfall | ||||||
| 74 mm | 82 mm | 72 mm | ||||
| Wind | ||||||
| 3 m/s | 3 m/s | 4 m/s | ||||
| Avg. water temperature | ||||||
| +14°C | +14°C | +14°C | ||||
| Humidity | ||||||
| 78% | 81% | 82% | ||||
| Air pressure | ||||||
| 1013 HPa | 1012 HPa | 1013 HPa | ||||
| Sunny days | ||||||
| 2 | 1 | 2 | ||||
| Cloudy days | ||||||
| 8 | 9 | 10 | ||||
| Rainy days | ||||||
| 20 | 21 | 18 | ||||
| Snowy days | ||||||
| 0 | 0 | 0 | ||||
August weather is still as ok as in July. The temperature levels stay the same in the area of +18°C for average maximum temperature during the day. Prepare for more rain. Average rainfall goes from 74 mm to 82 mm. Humidity rises from 78% to 81%. The average wind speed doesn’t change much during August, staying around 3 m/s. The days becoming less sunny, going from 2 sunny days in July to 1 in August.
September brings much the same weather, it remains ok.
Wind
The average wind speed is 4 m/s getting up to 8 m/s which is a medium breeze. You can feel it, especially getting out of the water.
The average wind speed in Belfast is gradually decreasing during August, going from 4 m/s to 3 m/s over the course of the month.
Rain
How was the weather last August in Belfast?
Climate Change over Years
The climate in Belfast in August has not changed much over the last 43 years.
The average temperature was the lowest in 1979 (+11°C) and the highest in 1995 (+14°C). The driest year was 2003 with only 711 mm of rainfall, and the wettest year was 2019 with 1255 mm.
FAQ
Is August a good time to visit Belfast?
Can you sunbathe in Belfast in August?
Can you swim in Belfast in August?
Is Belfast rainy in August?
Is it sunny in Belfast in August?
Other cities in United Kingdom
Monthly weather in Belfast
Source of the data
For this page, we’ve looked at the typical weather in Belfast, based on historical hourly weather data from January 1, 1979, to December 31, 2023.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.