May in Derry averages a daily high of 13.5°C with nights around 8°C. Expect roughly 17 wet days totalling 68.2mm. Demanding conditions — pack for it and plan indoor options.
Across the year, the best time to visit Derry is June–September.
Based on MALIN HEAD, EI (41.6km), 1995–2024. 30 years of May data.