July in Somerville averages a daily high of 28°C with nights around 19.2°C. Expect roughly 10 wet days totalling 95.1mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Somerville is May–September.
Based on BOSTON LOGAN INTERNATIONAL AIRPORT, MA US (8km), 1995–2024. 30 years of July data.