May in Glasgow averages a daily high of 15.3°C with nights around 6.8°C. Expect roughly 14.2 wet days totalling 57.1mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Glasgow is June–September.
Based on AUCHINCRUIVE, UK (47.3km), 1995–2024. 25 years of May data.