May in Norwalk averages a daily high of 22.6°C with nights around 9.3°C. Expect roughly 12.8 wet days totalling 105.3mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Norwalk is August–October.
Based on STAMFORD 5 N, CT US (11.7km), 1995–2024. 20 years of May data.