August weather forecast and climate
Washington, DC

Rows of jacaranda trees in spring in the tidal basin of the Washington Monument in Washington city, DC, USA
Rows of jacaranda trees in spring in the tidal basin of the Washington Monument in Washington city, DC, USA

Weather in August

The last month of the summer, August, is another warm month in Washington, District of Columbia, with average temperature varying between 68°F (20°C) and 85.8°F (29.9°C).

Temperature

In August, the average high-temperature is practically the same as in July - a moderately hot 85.8°F (29.9°C). In August, in Washington, District of Columbia, the average low-temperature is 68°F (20°C).

Heat index

In August, the average heat index is computed to be a torrid 95.5°F (35.3°C). Take special precautions - heat exhaustion and heat cramps are expected. Heatstroke may occur with lengthy activity.
Take into consideration that the heat index values are calculated for shade and light wind conditions. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature', 'feels like', 'real feel', or 'felt air temperature', combines air temperature and relative humidity to represent a human perceived temperature equivalent. Additional factors like activity, pregnancy, metabolic differences, and differences in body mass, height, and shape affect individual temperature impact. Be aware that direct exposure to sunlight increases heat impact and may raise the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Young children are generally more endangered than adults, as they usually less sweat. And also, due to larger skin surface relative to their small bodies and higher heat production as a result of their activity.
To prevent overheating and help regulate its internal temperature, the human body sweat and rely on the evaporation to cool down. When the relative humidity is high, the evaporation rate is reduced. The warmth is removed from the body at a lower rate, causing the body to retain more heat than it would in dry air. When heat gain surpasses the level the body can shed, body temperature begins to increase, and consequently, overheating and dehydration can occur, with varying severity.

Humidity

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

Rainfall

The month with the most rainfall is August when the rain falls for 15.5 days and typically aggregates up to 3.46" (88mm) of precipitation.

Snowfall

In Washington, District of Columbia, snow does not fall in April through November.

Daylight

In August, the average length of the day in Washington is 13.6h.

Sunshine

In August, the average sunshine is 10.3h.

UV index

In August, the average daily maximum UV index is 6. A UV Index of 6 to 7 symbolizes a high health vulnerability from unprotected exposure to the Sun's UV rays for the ordinary person.
Note: In August, the average maximum UV index of 6 translate into the following recommendations:
Take precautions and utilize sun safety practices. Protection against the skin and eye damage is required. 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. 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 temperature in August in Washington?

In Washington, District of Columbia, in August, the average high-temperature is 85.8°F (29.9°C), and the average low-temperature is 68°F (20°C). The average heat index (a.k.a. 'feels like', 'apparent temperature'), which combines relative humidity and air temperature, in August is computed to be 95.5°F (35.3°C).

What is the average humidity in August in Washington?

In Washington, District of Columbia, the average relative humidity in August is 72%.

What is the wettest month in Washington?

The month with the most rainfall in Washington is August when the rain falls for 15.5 days and typically aggregates up to 3.46" (88mm) of precipitation.

How many days does it rain in August in Washington?

In Washington, District of Columbia, during August, the rain falls for 15.5 days and regularly aggregates up to 3.46" (88mm) of precipitation.

When it does not snow in Washington?

In Washington snow does not fall in April through November.

What is the average length of the day in August in Washington?

In August, the average length of the day is 13.6h.

How long on average sun shines in August in Washington?

The average sunshine in August is 10.3h.

What is the UV index reading in August in Washington?

The average daily maximum UV index in August in Washington, District of Columbia, is 6. A UV Index of 6 to 7 symbolizes a high hazard to health from unprotected exposure to the UV radiation.

Average temperature in August
Washington, DC

Average temperature in August - Washington, DC
  • Average high temperature in August: 29.9°C

The warmest month (with the highest average high temperature) is July (31.1°C).
The month with the lowest average high temperature is January (4.8°C).

  • Average low temperature in August: 20°C

The month with the highest average low temperature is July (20.6°C).
The coldest month (with the lowest average low temperature) is January (-2.5°C).

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Average pressure in August
Washington, DC

Average pressure in August - Washington, DC
  • Average pressure in August: 1015.6mbar

The month with the highest atmospheric pressure is November (1020.6mbar).
The month with the lowest atmospheric pressure is June (1014.1mbar).

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Average wind speed in August
Washington, DC

Average wind speed in August - Washington, DC
  • Average wind speed in August: 8.1km/h

The windiest month (with the highest average wind speed) is March (12.7km/h).
The calmest month (with the lowest average wind speed) is August (8.1km/h).

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Average humidity in August
Washington, DC

Average humidity in August - Washington, DC
  • Average humidity in August: 72%

The month with the highest relative humidity is May (76%).
Months with the lowest relative humidity are April and July (71%).

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Average rainfall in August
Washington, DC

Average rainfall in August - Washington, DC
  • Average rainfall in August: 88mm

The wettest month (with the highest rainfall) is August (88mm).
The driest month (with the least rainfall) is January (40mm).

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Average rainfall days in August
Washington, DC

Average rainfall days in August - Washington, DC
  • Average rainfall days in August: 15.5 days

The month with the highest number of rainy days is July (16.4 days).
The month with the least rainy days is November (8.1 days).

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Average snowfall in August
Washington, DC

Average snowfall in August - Washington, DC
  • Average snowfall in August: 0mm

The month with the highest snowfall is January (55mm).
Months with the least snowfall are April, May, June, July, August, September, October and November (0mm).

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Average snowfall days in August
Washington, DC

Average snowfall days in August - Washington, DC
  • Average snowfall days in August: 0 days

Months with the highest number of snowfall days are January and February (3.8 days).
Months with the least snowfall days are April, May, June, July, August, September and October (0 days).

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Average daylight in August /
Average sunshine in August
Washington, DC

Average daylight in August / Average sunshine in August - Washington, DC
  • Average daylight in August: 13.6h

The month with the longest days is June (Average daylight: 14.9h).
The month with the shortest days is December (Average daylight: 9.5h).

  • Average sunshine in August: 10.3h

The month with the most sunshine is July (Average sunshine: 10.7h).
Months with the least sunshine are January, February and December (Average sunshine: 5.1).

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Average sunshine days in August
Washington, DC

Average sunshine days in August - Washington, DC
  • Average sunshine days in August: 13 days

The month with the most sunshine days is November (20 days).
The month with the least sunshine days is May (12.8 days).

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Average UV index in August
Washington, DC

Average UV index in August - Washington, DC
  • Average UV index in August: 6

The month with the highest UV index is June (UV index 7).
Months with the lowest UV index are January and December (UV index 2).

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Average cloud cover in August
Washington, DC

Average cloud cover in August - Washington, DC
  • Average cloud cover in August: 32

The month with the most cloud cover is March (Cloud cover 46).
The month with the least cloud cover is July (Cloud cover 30).

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Average visibility in August
Washington, DC

Average visibility in August - Washington, DC
  • Average visibility in August: 9km

Months with the highest visibility are January, February, March, April, June, July, August, September, October, November and December (9km).
The month with the lowest visibility is May (8km).

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