Boston Weather by Month: Temperatures, Rainfall and Snowfall

Boston has a humid continental climate with four distinct seasons: cold snowy winters, warm humid summers, and crisp transition months in spring and fall. The city averages 43.8 inches (1,112 mm) of precipitation annually spread evenly across the year, plus 49 inches of snow concentrated between December and March. The Atlantic Ocean moderates temperatures in spring and early summer but does little to warm the depths of January, when average highs stay around 36°F (2°C). For more details, see our best time to visit Boston guide.

Boston Weather by Month

January is the coldest month with average highs of 36°F (2°C) and lows of 22°F (-6°C). You will see 14 inches of snow on average and 3.4 inches of precipitation. Daylight runs from roughly 7:10 AM to 4:40 PM. Nor’easters can dump a foot or more in a single storm, shutting down Logan Airport and the MBTA. Pack a heavyweight down coat, waterproof boots, hat, and gloves. For more details, see our things to do in Boston guide.

February remains cold at 39°F (4°C) high and 24°F (-4°C) low, with 13 inches of snow. The month is marginally drier than January at 3.3 inches of precipitation. Days lengthen noticeably by late February, with sunset pushing past 5:30 PM. Frozen harbor, icy sidewalks, and wind chill below 0°F (-18°C) are common. February school vacation week drives up hotel prices in the second half of the month. For more details, see our Boston events and festivals guide.

March brings the first signs of thaw with highs reaching 45°F (7°C) and lows at 31°F (-1°C). Snow drops to 8 inches and precipitation is 3.9 inches. St. Patrick’s Day weekend is the first major event of the year. The weather is unpredictable: 60°F (16°C) one day, a nor’easter with 6 inches of snow the next. Pack layers and waterproof footwear, slush is everywhere. For more details, see our best neighborhoods in Boston guide.

April sees real spring at last: 56°F (13°C) high, 41°F (5°C) low. Snow falls below 2 inches on average and rainfall measures 3.8 inches. The Boston Marathon on Patriots’ Day (third Monday) runs rain or shine. Cherry blossoms and magnolias peak in the Public Garden around mid-April. A light jacket or trench coat with a sweater underneath handles most days. For more details, see our where to stay in Boston guide.

May is one of Boston’s best weather months: 66°F (19°C) high, 51°F (11°C) low, with 3.5 inches of rain over 12 days. Trees are fully leafed out by mid-month, and outdoor dining on Newbury Street and in the North End is in full swing. University graduations pack hotels from mid-May onward, book at least 6 weeks ahead. For more details, see our Boston travel tips guide.

June brings summer warmth at 76°F (24°C) high and 60°F (16°C) low, with 3.4 inches of rain. Humidity is moderate early in the month but builds toward July. Water temperature in Boston Harbor reaches 60°F (16°C), cold enough that only the brave swim without a wetsuit. Sunset is around 8:25 PM. Hotel prices climb steeply after Memorial Day.

July is the hottest month at 82°F (28°C) high and 66°F (19°C) low. Humidity peaks with dew points regularly above 65°F (18°C). Rain averages 3.6 inches, often from afternoon thunderstorms. Harbor water temperature reaches 66°F (19°C). Boston Harborfest over July 4th draws the year’s biggest crowds. Pack light cotton, sunscreen, and insect repellent for evenings on the Esplanade.

August is nearly identical to July: 80°F (27°C) high, 65°F (18°C) low, 3.6 inches of rain. Humidity peaks early in the month and begins to ease after mid-August. Harbor water hits its annual maximum of 68°F (20°C). College students return in the last week, filling restaurants and bars in Allston, Fenway, and Cambridge. Book hotels 4 to 6 weeks ahead.

September is the best weather month of the year: 73°F (23°C) high, 57°F (14°C) low, 3.5 inches of rain. Humidity drops sharply after Labor Day. Water temperature holds at 64°F (18°C) through mid-month. Clear blue skies and golden afternoon light make walking the Freedom Trail genuinely pleasant. Hotel prices stay high through foliage season.

October cools to 62°F (17°C) high and 46°F (8°C) low, with 3.9 inches of rain. Peak fall foliage in the Boston Common and Public Garden arrives between October 15 and 25, two weeks earlier in the suburbs. Head of the Charles Regatta on the third weekend brings 400,000 spectators. A medium-weight jacket, scarf, and comfortable walking shoes are the uniform.

November turns cold: 51°F (11°C) high, 37°F (3°C) low, 4.0 inches of precipitation. The first snow typically falls in the second half of the month, though accumulation is usually under 2 inches. Days shorten dramatically, with sunset before 4:30 PM after daylight saving time ends. Hotel prices drop significantly after Thanksgiving.

December averages 41°F (5°C) high and 27°F (-3°C) low, with 3.8 inches of precipitation including 9 inches of snow. The First Night Boston celebration on December 31 draws crowds for ice sculptures along the waterfront and fireworks over Boston Harbor at midnight. Hotel prices spike around Christmas week and New Year’s Eve. A heavy winter coat, snow boots, hat, and gloves are mandatory.

Boston Weather by Month: Quick Reference Table

Data source: NOAA/NWS Boston climate normals 1991-2020, Logan International Airport station. For a complete overview, visit our Boston guide hub page.