Boston Weather in August

August continues the warm and sunny weather for Boston, Massachusetts. Indeed, Boston's August climate is typically drier and less cloudy than other summer months.

This page gives detailed information on the typical August 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

80 °F	August average high	27 °C
65 °F	August average low	18 °C

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

Nearly every day in August warms to over 70 degrees Fahrenheit (21 degrees Celsius) 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 August.

At night, the thermometer dips to 60 °F (16 °C) or below on 5 days. August normally doesn't get as cold as 50 °F (10 °C).

Rain

3.2 in	total precipitation	82 mm
9 days	of rain

Half the time, Boston receives 1.8 to 4.4 inches (45 to 110 mm) of rainfall in August. One in four years has drier weather, while another one in four is wetter. None of the precipitation falls as snow.

Sun

65 %	sunshine
9 days	clear skies

The sun's rays reach the ground in Boston during 65 percent of daylight hours on average in August, for a total of 278 hours in the month. Typically on 9 days this month the sky is mainly clear, with at most 30 percent cloud cover.

Sunlight in August at Boston lasts for 13 hours and 49 minutes a day on average. The longest day of the month is the 1st with 14 hours and 26 minutes of daylight. By the end of the month, the days have shortened to 13:10 from sunrise to sunset. These durations of daylight can vary by a minute or two from year to year.

Humidity

71 %	August average humidity

The relative humidity in Boston during August usually peaks at 82 percent in the morning then drops to 59 percent by early afternoon.

Local Time	1 am	4 am	7 am	10 am	1 pm	4 pm	7 pm	10 pm
Humidity %	79	82	77	64	59	61	69	76

Wind

10.8 mph

August wind speed average

17.4 kph

The wind at Boston is calmest overall during August.

Storms

2 days	rainfall of 0.5 inches (13 mm) or more
3 days	with thunderstorms in August
6 %	chance a named storm approaches

There's a 2 percent probability that a hurricane will approach within 100 miles (165 km) of Boston during August. The chance of a major hurricane (category 3 to 5) reaching the area is 1 percent.