May in Tallinn averages a daily high of 15.5°C with nights around 5.3°C. Expect roughly 9.1 wet days totalling 37.5mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Tallinn is June–August.
Based on TALLINN, EN (9.6km), 1995–2024. 30 years of May data.