May in Hämeenlinna averages a daily high of 16.5°C with nights around 5.4°C. Expect roughly 9.7 wet days totalling 34.5mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Hämeenlinna is June–August.
Based on HAMEENLINNA KATINEN, FI (1.7km), 1995–2024. 23 years of May data.