August weather forecast
Washington, DC

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.