Boston weather in September 2026
Expect daytime maximum temperatures of 23°C in Boston, Massachusetts in September based on long-term weather averages. There are 8 hours of sunshine per day on average with typically 82 mm of rainfall in the month.
- 23°C max day temperature
23 - 8 hours of sunshine per day
- 8 days with some rainfall
8 - 12°C min night temperature
12 - 12 hours of daylight per day
12 - No heat & humidity
0 - 82 mm of monthly rainfall
82 - 6 (High) UV index
6 - 16°C sea temperature
16
