August weather forecast and climate
Boston, MA

A beautiful natural park with the George Washington Monument in Boston, Massachusetts
A beautiful natural park with the George Washington Monument in Boston, Massachusetts

Weather in August

The last month of the summer, August, is also a moderately hot month in Boston, Massachusetts, with temperature in the range of an average high of 80.4°F (26.9°C) and an average low of 64°F (17.8°C).

Temperature

In August, the average high-temperature is essentially the same as in July - a still warm 80.4°F (26.9°C). In Boston, the average low-temperature is 64°F (17.8°C).

Humidity

The average relative humidity in August is 72%.

Rainfall

In Boston, it is raining for 11.7 days, with typically 1.61" (41mm) of accumulated precipitation. In Boston, during the entire year, the rain falls for 141.4 days and collects up to 27.2" (691mm) of precipitation.

Snowfall

In Boston snow does not fall in June through September.

Ocean temperature

With an average ocean temperature of 68°F (20°C), August is the month with the warmest seawater.
Note: Swimming in 68°F (20°C) is not enjoyable for the majority. Controlling breathing becomes progressively more difficult as surface water temperature decreases below 69.8°F (21°C).

Daylight

The average length of the day in August is 13.8h.

Sunshine

With an average of 10.5h of sunshine, August has the most sunshine of the year.

UV index

Months with the highest UV index in Boston are June through August, with an average maximum UV index of 6. A UV Index of 6 to 7 symbolizes a high health risk from unsafe exposure to the UV radiation for the average person.
Note: In August, the average maximum UV index of 6 translate into the following recommendations:
Take precautions against overexposure. Fair-skinned people may get burned in less than 20 minutes. Seek shade and minimize exposure to direct Sun in a period between 10 a.m. and 4 p.m. when UV radiation is most intense; keep in mind that shade structures like parasols or canopies do not provide perfect sun protection. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
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FAQ

What is the average humidity in August in Boston?

The average relative humidity in August in Boston is 72%.

How many days does it rain in August in Boston?

In Boston, Massachusetts, in August, during 11.7 rainfall days, 1.61" (41mm) of precipitation is typically accumulated.

When it does not snow in Boston?

June through September are months without snowfall.

What month is the ocean warmest in Boston?

The month with the warmest seawater is August, with an average ocean temperature of 68°F (20°C).

What is the ocean temperature in August in Boston?

In August, the average ocean temperature in Boston, Massachusetts, is 68°F (20°C). Swimming in 68°F (20°C) is not enjoyable for the majority. Controlling breathing becomes progressively more difficult as surface water temperature decreases below 69.8°F (21°C).

How many hours of daylight does Boston have in August?

The average length of the day in August in Boston, Massachusetts, is 13.8h.

What month has the most sunshine in Boston?

The month with the most sunshine is August, with an average of 10.5h of sunshine.

How many hours of sunshine does Boston have in August?

In Boston, the average sunshine in August is 10.5h.

What is the month with the highest UV index in Boston?

Months with the highest UV index are June through August, with an average maximum UV index of 6.

What is the UV index reading in August in Boston?

In August, the average daily maximum UV index in Boston, Massachusetts, is 6. A UV Index reading of 6 to 7 represents a high health risk from the exposure to the Sun's UV radiation.

Average temperature in August
Boston, MA

Average temperature in August - Boston, MA
  • Average high temperature in August: 26.9°C

The warmest month (with the highest average high temperature) is July (27.6°C).
The month with the lowest average high temperature is January (1.2°C).

  • Average low temperature in August: 17.8°C

The month with the highest average low temperature is July (18.3°C).
The coldest month (with the lowest average low temperature) is January (-5.2°C).

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Average pressure in August
Boston, MA

Average pressure in August - Boston, MA
  • Average pressure in August: 1015.1mbar

The month with the highest atmospheric pressure is November (1018.1mbar).
The month with the lowest atmospheric pressure is June (1013.4mbar).

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Average wind speed in August
Boston, MA

Average wind speed in August - Boston, MA
  • Average wind speed in August: 9.9km/h

The windiest month (with the highest average wind speed) is January (15.9km/h).
The calmest month (with the lowest average wind speed) is August (9.9km/h).

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Average humidity in August
Boston, MA

Average humidity in August - Boston, MA
  • Average humidity in August: 72%

The month with the highest relative humidity is February (77%).
The month with the lowest relative humidity is April (69%).

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Average rainfall in August
Boston, MA

Average rainfall in August - Boston, MA
  • Average rainfall in August: 41mm

The wettest months (with the highest rainfall) are March, April and December (74mm).
The driest month (with the least rainfall) is September (32mm).

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Average rainfall days in August
Boston, MA

Average rainfall days in August - Boston, MA
  • Average rainfall days in August: 11.7 days

The month with the highest number of rainy days is May (15.3 days).
The month with the least rainy days is January (7.9 days).

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Average snowfall in August
Boston, MA

Average snowfall in August - Boston, MA
  • Average snowfall in August: 0mm

The month with the highest snowfall is February (120mm).
Months with the least snowfall are June, July, August and September (0mm).

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Average snowfall days in August
Boston, MA

Average snowfall days in August - Boston, MA
  • Average snowfall days in August: 0 days

Months with the highest number of snowfall days are January and February (7.6 days).
Months with the least snowfall days are June, July, August and September (0 days).

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Average sea temperature in August
Boston, MA

Average sea temperature in August - Boston, MA
  • Average sea temperature in August: 20°C

The best month for swimming (with the highest average sea temperature) is August (20°C).
The coldest month (with the lowest average sea temperature) is February (3.4°C).

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Average daylight in August /
Average sunshine in August
Boston, MA

Average daylight in August / Average sunshine in August - Boston, MA
  • Average daylight in August: 13.8h

The month with the longest days is June (Average daylight: 15.2h).
The month with the shortest days is December (Average daylight: 9.1h).

  • Average sunshine in August: 10.5h

The month with the most sunshine is August (Average sunshine: 10.5h).
The month with the least sunshine is February (Average sunshine: 4.6h).

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Average sunshine days in August
Boston, MA

Average sunshine days in August - Boston, MA
  • Average sunshine days in August: 17 days

The month with the most sunshine days is September (17.7 days).
The month with the least sunshine days is April (13 days).

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Average UV index in August
Boston, MA

Average UV index in August - Boston, MA
  • Average UV index in August: 6

Months with the highest UV index are June, July and August (UV index 6).
Months with the lowest UV index are January, February, March, November and December (UV index 2).

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Average cloud cover in August
Boston, MA

Average cloud cover in August - Boston, MA
  • Average cloud cover in August: 32

The month with the most cloud cover is March (Cloud cover 51).
The month with the least cloud cover is August (Cloud cover 32).

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Average visibility in August
Boston, MA

Average visibility in August - Boston, MA
  • Average visibility in August: 9km

Months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (9km).
Months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (9km).

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