August weather forecast
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 also a moderately hot month in Washington, District of Columbia, with an average temperature fluctuating between 68°F (20°C) and 85.8°F (29.9°C).

Temperature

In August, the average high-temperature is essentially the same as in July - a moderately hot 85.8°F (29.9°C). The average low-temperature, in August, is 68°F (20°C).

Heat index

In August, the average heat index is calculated to be a sweltering 95.5°F (35.3°C). Take extra precautions, as heat cramps and heat exhaustion are possible. Sustained activity may result in heatstroke.
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 'felt air temperature', 'apparent temperature', 'feels like', or 'real feel', is a calculated temperature value of how hot it feels when the moisture in the air is factored in. This effect is individual, with diverse people perceiving weather differently for numerous reasons (clothing, wind, metabolic differences), and activity. Bear in mind that direct sunshine exposure increases weather impact, and may raise heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. 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.
The human body cools itself through perspiration, as excessive warmth is removed from the body through sweat evaporation. High relative humidity reduces the evaporation rate, resulting in a lower heat removal rate from the body, causing the perception of being overheated. 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

August is the month with the most rainfall in Washington. Rain falls for 15.5 days and accumulates 3.46" (88mm) of precipitation.

Snowfall

April through November are months without snowfall.

Daylight

In Washington, the average length of the day in August is 13h and 38min.
On the first day of August in Washington, sunrise is at 6:09 am and sunset at 8:19 pm. On the last day of the month, sunrise is at 6:36 am and sunset at 7:40 pm EDT.

Sunshine

In August, the average sunshine is 10.3h.

UV index

The average daily maximum UV index in August is 6. A UV Index estimate of 6 to 7 represents a high health hazard from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: The average daily UV index of 6 in August transform into the following instructions:
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. A wide-brim hat offers excellent sun protection for the 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.
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FAQ

What is the temperature in August in Washington?

In August, in Washington, District of Columbia, 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. 'felt air temperature', 'real feel'), which takes the relative humidity and factors it into the air temperature reading, in August is calculated to be 95.5°F (35.3°C).

What is the average humidity in August in Washington?

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

What is the rainiest month in Washington?

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.

How much does it rain in Washington in August?

In Washington, District of Columbia, in August, during 15.5 rainfall days, 3.46" (88mm) of precipitation is typically accumulated.

When it does not snow in Washington?

April through November are months without snowfall in Washington, District of Columbia.

How many hours of daylight does Washington have in August?

In Washington, the average day length in August is 13h and 38min.

When is the sunrise / sunset in August in Washington?

On the first day of August in Washington, sunrise is at 6:09 am and sunset at 8:19 pm. On the last day of the month, sunrise is at 6:36 am and sunset at 7:40 pm EDT.

How many hours of sunshine does Washington have in August?

In Washington, District of Columbia, the average sunshine duration in August is 10.3h.

How high is the UV index 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 health vulnerability from exposure to the Sun's UV radiation.

Average temperature in August
Washington, DC

Average temperature in August - Washington, DC
  • Average high temperature in August: 85.8°F

The warmest month (with the highest average high temperature) is July (88°F).
The month with the lowest average high temperature is January (40.6°F).

  • Average low temperature in August: 68°F

The month with the highest average low temperature is July (69.1°F).
The coldest month (with the lowest average low temperature) is January (27.5°F).

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Average pressure in August
Washington, DC

Average pressure in August - Washington, DC
  • Average pressure in August: 29.99"

The month with the highest atmospheric pressure is November (30.14").
The month with the lowest atmospheric pressure is June (29.95").

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Average wind speed in August
Washington, DC

Average wind speed in August - Washington, DC
  • Average wind speed in August: 5mph

The windiest month (with the highest average wind speed) is March (7.9mph).
The calmest month (with the lowest average wind speed) is August (5mph).

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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%).
The 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: 3.46"

The wettest month (with the highest rainfall) is August (3.46").
The driest month (with the least rainfall) is January (1.57").

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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: 0"

The month with the highest snowfall is January (2.17").
The months with the least snowfall are April, May, June, July, August, September, October and November (0").

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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

The months with the highest number of snowfall days are January and February (3.8 days).
The 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: 13h and 38min

The month with the longest days is June (Average daylight: 14h and 51min).
The month with the shortest days is December (Average daylight: 9h and 29min).

  • Average sunshine in August: 10.3h

The month with the most sunshine is July (Average sunshine: 10.7h).
The 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).
The 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: 6mi

The months with the highest visibility are January, February, March, April, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is May (5mi).

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