May in Słupsk averages a daily high of 15.9°C with nights around 6.4°C. Expect roughly 10.6 wet days totalling 47.9mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Słupsk is June–August.
Based on LEBA, PL (45.5km), 1995–2024. 30 years of May data.