August weather forecast and climate
Boston, MA

A beautiful natural park with the George Washington Monument in Boston, Massachusetts, with a sneak view of the city skyscrapers
A beautiful natural park with the George Washington Monument in Boston, Massachusetts, with a sneak view of the city skyscrapers
The last month of the summer, August, is another warm month in Boston, Massachusetts, with average temperature fluctuating between 80.4°F (26.9°C) and 64°F (17.8°C).

Temperature

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

Humidity

The average relative humidity in Boston is 72%.

Rainfall

In August, in Boston, the rain falls for 11.7 days. Throughout August, 1.61" (41mm) of precipitation is accumulated. Throughout the year, there are 141.4 rainfall days, and 27.2" (691mm) of precipitation is accumulated.

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: For most, swimming in 68°F (20°C) is not an enjoyable activity. Furthermore, controlling your breathing becomes progressively more difficult as the water temperature decreases from 69.8°F (21°C) to 59°F (15°C).

Daylight

In August, the average length of the day is 13.8h.

Sunshine

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

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 the exposure to the Sun's UV radiation for the ordinary person.
Note: The daily maximum UV index of 6 interpret into the following advice:
Take precautions against overexposure. Protection against sun damage is needed. The Sun's UV radiation is most powerful between 10 a.m. and 4 p.m. To the extent possible, limit exposure to the direct sun during these hours. A wide-brim hat offers excellent sun protection for eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun.

What is the temperature in August in Boston?

The average high-temperature, in August, is 80.4°F (26.9°C), while the average low-temperature is 64°F (17.8°C).

What is the average humidity in August in Boston?

In Boston, the average relative humidity in August is 72%.

How much does it rain in Boston in August?

In Boston, in August, it is raining for 11.7 days, with typically 1.61" (41mm) of accumulated precipitation.

When it does not snow in Boston?

In Boston snow does not fall in June through September.

What is the month with the warmest ocean 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 is 68°F (20°C). For swimming, a surface water temperature of 68°F (20°C) is not enjoyable for the majority. It is not considered safe, as controlling breathing becomes progressively more difficult as water temperature decreases below 69.8°F (21°C).

How many hours of daylight does Boston have in August?

In August, the average length of the day is 13.8h.

What month has the most sunshine in Boston?

August has the most sunshine of the year in Boston, Massachusetts, with an average of 10.5h of sunshine.

How many hours of sunshine does Boston have in August?

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

When is the highest UV index in Boston?

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

How high is the UV index in August in Boston?

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

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).

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).

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%).

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).

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).

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).

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).

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).

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).

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).

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).

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).

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).