December in Lancaster averages a daily high of 6.6°C with nights around -2.5°C. Expect roughly 10.9 wet days totalling 90.1mm. A hard month to visit for comfort alone.
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 December data.