May in Grimsby averages a daily high of 16.6°C with nights around 7.4°C. Expect roughly 12 wet days totalling 54.4mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Grimsby is June–September.
Based on WADDINGTON, UK (59.6km), 1995–2024. 29 years of May data.