May in Southampton averages a daily high of 17.6°C with nights around 7.4°C. Expect roughly 11.2 wet days totalling 53.4mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Southampton is June–September.
Based on HURN, UK (33.2km), 1995–2024. 30 years of May data.