WeatherArchive / Climate averages / Boston
Boston weather by month: climate averages
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.
Boston weather month by month
The wettest month in Boston is March, averaging 4.5 in (114 mm); the driest is February at 3.3 in (85 mm). May has the most days with at least 1 mm of rain (about 11). July is the sunniest month, with about 11.5 hours of sunshine a day, against 5.8 hours in December. If you like average highs between 64 °F and 82 °F (18–28 °C) with few rainy days, aim for July, August and September.
Planning a particular day? See how often that date was wet or hot over 30 years with the event weather odds, or look up what the weather actually was on any past date in the historical weather archive.
Questions people ask
What is the warmest month in Boston?
July, with an average daily high of 82°F (28°C) over 1996–2025.
What is the coldest month in Boston?
January, when nights average about 20°F (-7°C).
What is the rainiest month in Boston?
March has the most precipitation (about 4.5 in (114 mm)), and May has the most rainy days (about 11 days with 1 mm or more). The driest month is February.
How much sunshine does Boston get?
About 8.6 hours of bright sunshine a day averaged over the year, from 5.8 h in December to 11.5 h in July. Sunshine here is the model’s estimate of hours with direct sun, not hours of daylight.
What is the best month to visit Boston for mild weather?
By average high between 64 °F and 82 °F (18–28 °C) and the fewest rainy days: July, August, September. Prices, crowds and events are not included.