May in Plymouth averages a daily high of 16.3°C with nights around 8.7°C. Expect roughly 12.6 wet days totalling 62mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Plymouth is June–September.
Based on PLYMOUTH MOUNTBATTEN, UK (2.5km), 1995–2024. 29 years of May data.