September in Lancaster averages a daily high of 25.4°C with nights around 13.6°C. Expect roughly 9.3 wet days totalling 120mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Lancaster is May–June.
Based on LANCASTER 2 NE FILT PLANT, PA US (3km), 1995–2024. 29 years of September data.