Boston Weather in July

Boston, Massachusetts can expect hot and sunny summer weather in July. This month's climate is the hottest all year for Boston with daily highs averaging over 80 degrees Fahrenheit (27 degrees Celsius). July is also the city's sunniest month.

This page gives detailed information on the typical July temperature, precipitation, sun, humidity, wind and storms for Boston. The numbers here are historical averages based on climate data gathered at Boston's Logan International Airport, located on the waterfront next to Boston Harbor.

Temperature Weather iconTemperature

82 °F July average high 28 °C
66 °F July average low 19°C

July is Boston's hottest month with overall temperatures peaking from the 18th to 22nd. These dates have daily highs averaging 83 °F (28 °C) and lows of 67 °F (19 °C).

20 days 80 °F max. or more (27 °C)
25 days 70 °F min. or less (21 °C)

Nearly every day in July warms to over 70 °F (21 °C) in Boston. The city averages six days this month when the thermometer reaches into the 90s °F (over 32 °C). Temperatures above 100 °F (38 °C) are not expected here during July.

At night, the thermometer dips to 60 °F (16 °C) or below on 3 days. July does not normally cool down to 50 °F (10 °C).

Rainy Weather iconRain

3.3 in total precipitation 83 mm
9 days of rain

Half the time, Boston receives 2.1 to 4.4 inches (52 to 112 mm) of rainfall in July. One in four years has drier weather, while another one in four is wetter. None of the precipitation falls as snow.

Sunny Weather iconSun

65 % sunshine
7 days clear skies

July is Boston's sunniest month. The sun's rays reach the ground in Boston during 65 percent of daylight hours on average in July, for a total of 300 hours in the month. Typically on 7 days this month the sky is mainly clear, with at most 30 percent cloud cover.

Sunlight in July at Boston lasts for 14 hours and 53 minutes a day on average. The longest day of the month is the 1st with 15 hours and 13 minutes of daylight. By the end of the month, the days have shortened to 14:28 from sunrise to sunset. These durations can vary by a minute or two from year to year.

Humid Weather iconHumidity

68 % July average humidity

The relative humidity in Boston during July usually peaks at 80 percent in the morning then drops to 57 percent by early afternoon.

Local Time1 am4 am7 am10 am1 pm4 pm7 pm10 pm
Humidity % 77 80 74 62 57 58 66 74

Windy Weather iconWind

11.0 mph July wind speed average 17.7 kph

Boston's sea breeze usually keeps afternoon temperatures from getting overly hot in areas near the coast.

Stormy Weather iconStorms

2 days rainfall of 0.5 inches (13 mm) or more
4 days with thunderstorms in July
4 % chance a named storm approaches

Boston usually sees more thunderstorms in July than any other month.

There's a 4 percent probability that a named tropical storm will approach within 100 miles (165 km) of Boston during July. It's unlikely that any storm in the area will be as severe as a hurricane.


The weather data here are long-term averages provided by the US National Centers for Environmental Information (NCEI). Temperature and precipitation are 1991-2020 normals while humidity and thunderstorms are 1961-1990 normals. The named storm probabilities come from the Atlantic Oceanographic and Meteorological Laboratory, Hurricane Research Division.

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