May in Siedlce averages a daily high of 19.5°C with nights around 8°C. Expect roughly 12.9 wet days totalling 65.7mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Siedlce is May–September.
Based on SIEDLCE, PL (9.5km), 1995–2024. 30 years of May data.