October in New Haven averages a daily high of 18.2°C with nights around 8.6°C. Expect roughly 10.6 wet days totalling 102.2mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit New Haven is May–June.
Based on NEW HAVEN TWEED AIRPORT, CT US (6.4km), 1995–2024. 23 years of October data.