July in Derry averages a daily high of 16.9°C with nights around 12.2°C. Expect roughly 19.1 wet days totalling 90.3mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Derry is June–September.
Based on MALIN HEAD, EI (41.6km), 1995–2024. 29 years of July data.