September in Plainfield averages a daily high of 25.9°C with nights around 13.4°C. Expect roughly 9.5 wet days totalling 119.3mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Plainfield is May–June.
Based on CANOE BROOK, NJ US (13km), 1995–2024. 30 years of September data.