August in Belfast averages a daily high of 19.2°C with nights around 11.8°C. Expect roughly 16.5 wet days totalling 88.3mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Belfast is June–September.
Based on STORMONT CASTLE, UK (6.3km), 1995–2024. 28 years of August data.