May in Lancaster averages a daily high of 23.2°C with nights around 10.4°C. Expect roughly 12.9 wet days totalling 93.6mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Lancaster is May–June.
Based on LANCASTER 2 NE FILT PLANT, PA US (3km), 1995–2024. 30 years of May data.