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 °F (27 °C). July is also the city's sunniest month.

This page gives detailed information on the typical July weather for Boston.

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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

81 °F July average high 27 °C
65 °F July average low 19°C

In most years, Boston averages a daily maximum temperature for July that's between 79 and 84 degrees Fahrenheit (26 to 29 degrees Celsius). The minimum temperature usually falls between 64 and 67 °F (18 to 20 °C).

July is Boston's hottest month overall, with temperatures peaking on the 22nd and 23rd. These dates have daily highs averaging 81.8 °F (27.7 °C) and lows of 66.0 °F (18.9 °C).

18 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 4 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 4 days. July does not normally have weather as cold as 50 °F (10 °C).

Rainy Weather iconRain

3.4 in total precipitation 87 mm
10 days of rain

Half the time, Boston receives 2 to 4 inches (53 to 113 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.


These weather data are long-term historical averages provided by the National Climatic Data Center of the United States. The temperature and precipitation numbers are 1981-2010 normals while the humidity and thunderstorm statistics are 1961-1990 normals. The named storm probabilities come from the Atlantic Oceanographic and Meteorological Laboratory, Hurricane Research Division.

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