May in London averages a daily high of 19.6°C with nights around 7.9°C. Expect roughly 11.8 wet days totalling 85.2mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit London is May–September.
Based on LONDON CS, ON CA (8.7km), 1995–2024. 20 years of May data.