September in Norwalk averages a daily high of 25.1°C with nights around 13.1°C. Expect roughly 8.4 wet days totalling 128.2mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Norwalk is August–October.
Based on STAMFORD 5 N, CT US (11.7km), 1995–2024. 18 years of September data.