March in South Boston averages a daily high of 8°C with nights around -0.2°C. Expect roughly 11.1 wet days totalling 101.6mm. Demanding conditions — pack for it and plan indoor options.
Across the year, the best time to visit South Boston is May–September.
Based on BOSTON LOGAN INTERNATIONAL AIRPORT, MA US (4.5km), 1995–2024. 30 years of March data.