Boston Climate — Average Highs, Lows & Rainfall by Month
Boston has a temperate climate with four distinct seasons. Daytime temperatures average 29°C / 83°F in July, the warmest month, and drop to 3°C / 37°F in January, the coldest. Overnight lows in January average -6°C / 22°F. Boston receives about 1214 mm of rain a year across roughly 125 wet days, with July the wettest month.
Averages for 2021–2025 · Open-Meteo Historical Weather API (ERA5 reanalysis) · Updated 2026-10-05
Monthly averages in Boston
Average daytime high, overnight low and rainfall for each month of the year.
| Month | Avg high | Avg low | Rainfall | Wet days |
|---|---|---|---|---|
| January | 3°C / 37°F | -5°C / 23°F | 113 mm | 11 |
| February | 4°C / 39°F | -6°C / 22°F | 78 mm | 9 |
| March | 9°C / 49°F | -1°C / 31°F | 113 mm | 11 |
| April | 14°C / 57°F | 4°C / 40°F | 86 mm | 10 |
| May | 20°C / 68°F | 10°C / 50°F | 112 mm | 11 |
| June | 26°C / 78°F | 16°C / 60°F | 77 mm | 11 |
| July | 29°C / 83°F | 19°C / 67°F | 134 mm | 14 |
| August | 27°C / 81°F | 18°C / 64°F | 89 mm | 12 |
| September | 23°C / 73°F | 15°C / 58°F | 129 mm | 10 |
| October | 18°C / 64°F | 9°C / 49°F | 110 mm | 8 |
| November | 11°C / 52°F | 2°C / 36°F | 65 mm | 7 |
| December | 6°C / 42°F | -2°C / 28°F | 111 mm | 11 |
Best time to visit Boston
June, August, May offer the most comfortable weather in Boston: mild daytime temperatures with the year's lowest rainfall — June averages 26°C (78°F); August averages 27°C (81°F); May averages 20°C (68°F).
Boston climate FAQ
- What is the hottest month in Boston?
- July is the hottest month in Boston, with average daytime highs of 29°C / 83°F and overnight lows of 19°C / 67°F (averages for 2021–2025).
- What is the coldest month in Boston?
- January is the coldest month in Boston, with average highs of 3°C / 37°F and lows of -5°C / 23°F.
- How much rain does Boston get a year?
- Boston receives about 1214 mm of rainfall a year, spread over roughly 125 wet days. July is the wettest month (134 mm on average) and November the driest (65 mm).
- When is the best time to visit Boston?
- June, August, May are the most comfortable months in Boston: mild daytime temperatures with the least rainfall of the year.
Want today's conditions instead of averages?
See live weather in Boston →Source: Open-Meteo Historical Weather API (ERA5 reanalysis), Open-Meteo. Averages are daily means across 2021–2025 and are rounded for display — for a live forecast see the Boston weather page.