August weather forecast
Washington, DC

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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

August maintains the summer's heat in Washington, D.C. but initiates a subtle, unnoticeable descent towards autumn. With similar temperatures to July, this month still provides an ample window for tourists. As outdoor activities flourish, locals and tourists flock to sidewalk cafes, breweries, and rooftop bars. Nonetheless, one must bear in mind that this month sees the highest average rainfall of 3.46" (88mm). Therefore, carrying an umbrella is highly recommended.

Temperature

Washington, District of Columbia, sees the arrival of August with an average high-temperature of a moderately hot 85.8°F (29.9°C), indicating a subtle variation from July. During the month of August, Washington anticipates a mean low-temperature of 68°F (20°C).

Heat index

In August, the average heat index is evaluated at a fiery hot 95°F (35°C). Greater safety measures are needed, risk of heat exhaustion and heat cramps is high. Continuous activity might trigger heatstroke.
Factoring in the heat index, values are geared towards shaded areas with light breezes. Under direct sunshine, the heat index values might be elevated by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'feels like', determines the feeling of heat when you account for the relative humidity. This impact is subjective, influenced by the person's physical activity and individual heat perception, affected by factors including wind, attire, and metabolic differences. Under direct sun rays, the felt temperature might be heightened, with the heat index increasing by 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly meaningful for babies and toddlers. Children often fail to understand the importance of rest and rehydration. Thirst is a late manifestation of dehydration - hence, it is crucial to stay hydrated, especially during ongoing physical activities.
When it comes to cooling down, the human body's primary method is through perspiration, making use of sweat evaporation to eliminate excess heat. Greater relative humidity lessens the rate of evaporation, thus decreasing the body's heat dispersal, which gives rise to a sensation of overheating. Overheating and potential dehydration arise when body heat gain eclipses its release capability.

Humidity

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, snow does not fall in April through November.

Daylight

In Washington, the average length of the day in August is 13h and 38min.
On the first day of August, 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 7:39 pm EDT.

Sunshine

The average sunshine in August is 10.3h.

UV index

The average daily maximum UV index in August in Washington is 6. A UV Index reading of 6 to 7 represents a high health vulnerability from unprotected exposure to Sun's UV rays for the ordinary person.
Note: The maximum daily UV index of 6 in August converts into the following recommendations:
Follow precautions and abide by sun safety rules. Deterrence of sunburn is imperative. It's important to stay in the shade and limit exposure to the sun from 10 a.m. to 4 p.m., when UV radiation is most intense, although remember that shade structures may not provide full sun protection. Using UVA and UVB-protective sunglasses and sun-protective clothing is effective against UV radiation.
Updated: Feb 10, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How hot does it get in Washington in August?

In Washington, 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. 'felt air temperature', 'apparent temperature'), which factors the actual air temperature with the relative humidity, in August is evaluated at 95°F (35°C).

What is the average humidity in August in Washington?

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

What is the wettest month in Washington?

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

How much does it rain in Washington in August?

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

How many hours of daylight does Washington have in August?

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

When are sunrise and sunset in August in Washington?

In August, on the first day of the month, 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 7:39 pm EDT.

How long on average sun shines in August in Washington?

The average sunshine duration in August is 10.3h.

What is the UV index intensity in August in Washington?

In August, the average daily maximum UV index in Washington is 6. A UV Index reading of 6 to 7 represents a high health risk from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

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).

Average pressure in August
Washington, DC

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

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

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).

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%).

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").

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).

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").

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).

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 4min

The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 30min).

  • Average sunshine in August: 10h and 2min

The month with the most sunshine is July (Average sunshine: 10h and 42min).
The months with the least sunshine are January, February and December (Average sunshine: 5h and 6min).

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).

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).

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).

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).

Washington, District of Columbia, USA

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