WeatherArchive / Climate averages / Boston
Boston climate: average weather by month
Boston averages 51°F (11°C) over the year. July is warmest, with highs around 82°F (28°C); January is coldest, with lows near 20°F (-7°C). About 45 inches (1154 mm) of precipitation falls on roughly 121 days a year, from 30 years of ERA5 data (1996–2025).
| Month | Avg high | Avg low | Precip. | Days ≥1 mm | Sunshine / day |
|---|---|---|---|---|---|
| January | 1.9°C | -6.6°C | 97.7 mm | 10.3 | 6.3 h |
| February | 3.5°C | -5.7°C | 84.5 mm | 9.2 | 7.2 h |
| March | 7.5°C | -1.9°C | 113.8 mm | 10.9 | 8.1 h |
| April | 13.5°C | 3.9°C | 102.8 mm | 11.0 | 8.9 h |
| May | 19.1°C | 9.7°C | 89.3 mm | 11.1 | 9.9 h |
| June | 24.4°C | 15.2°C | 91.0 mm | 10.7 | 10.8 h |
| July | 27.9°C | 18.8°C | 86.5 mm | 10.6 | 11.5 h |
| August | 26.9°C | 18.1°C | 84.6 mm | 9.8 | 10.8 h |
| September | 22.9°C | 14.6°C | 92.2 mm | 8.4 | 9.1 h |
| October | 16.5°C | 8.5°C | 112.0 mm | 9.7 | 7.7 h |
| November | 10.2°C | 2.5°C | 87.1 mm | 8.9 | 6.5 h |
| December | 5.0°C | -2.6°C | 112.5 mm | 10.6 | 5.8 h |
Record high 1996–2025: 40.3°C on 2011-07-22. Record low: -26.4°C on 2016-02-14.
Source: Open-Meteo Historical Weather API (CC BY 4.0). Values are ERA5 reanalysis model data on a ~9–25 km grid, not readings from a weather station, so a single town’s thermometer can differ by a few degrees and local showers can be missed. Grid cell 42.36, -71.13 at 9 m. For snowfall, humidity and a best-time-to-visit score, open Boston in the climate tool.