August Weather in Washington, United States

Last updated: June 24, 2025

In August, the average temperature in Washington, United States hovers around 21°C (70°F). You'll experience a minimum of 8°C (47°F) and a maximum of 33°C (91°F), so pack for a range of weather! Expect about 143 mm (5.6 in) of precipitation over 13 days, with an average humidity of 64%. Be prepared for a mix of sunny days and occasional showers!

August Temperature in Washington

In August in Washington, the average temperature is 21°C (70°F), with maximums reaching up to 33°C (91°F) and minimums dipping as low as 8°C (47°F). This makes it an ideal time for travelers to enjoy a mix of warm days and cooler evenings, perfect for outdoor activities and sightseeing.

August Weather in Washington: Daily Temperature Highs, Lows, and Averages

The chart illustrates August temperature patterns in Washington, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Washington, August typically has an average temperature of 21°C (70°F), with highs reaching up to 33°C (91°F) and lows dropping to around 8°C (47°F).

Data source: Temperature data for Washington generated using information from the Copernicus Climate Change Service.

August Precipitation in Washington

In Washington in August, the precipitation amount is 143 mm (5.6 in) over a span of 13 days.

August Precipitation Trends in Washington

The chart displays monthly precipitation patterns in Washington, with values for each month alongside August’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how August’s conditions compare to those of other months. In Washington, August typically receives around 143 mm (5.6 inches) of precipitation spread over approximately 13 days.

Data source: Precipitation data for August generated using information from the Copernicus Climate Change Service.

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

August Humidity in Washington

In Washington in August humidity is 64%. With an average temperature of 21°C (70°F), this humidity feels like a warm embrace, making it comfortable for traveling during the day, albeit slightly sticky in the afternoons.

August Average Humidity in Washington

This chart illustrates the average monthly humidity levels in Washington, with August’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In August, average humidity in Washington is approximately 64%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for August generated using information from the Copernicus Climate Change Service.

August UV Index in Washington

In Washington in August, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Washington.

Maximum UV Index Levels in Washington for August

The chart shows the monthly maximum UV Index (UVI) for Washington in August, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In August, the maximum UV index in Washington typically reaches 9, which falls under the very high exposure category.

Data source: Washington August UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

How August Weather in Washington Compares to Other Months

Weather in Washington varies notably across the year, with each month offering distinct climate conditions. This page compares August’s weather to other months in Washington, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Washington, showing how August’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-4°C (26°F)	86 mm (3.4 inches)	89%	moderate
February Weather	-2°C (29°F)	104 mm (4.1 inches)	88%	moderate
March Weather	1°C (34°F)	90 mm (3.6 inches)	86%	high
April Weather	8°C (46°F)	157 mm (6.2 inches)	84%	very high
May Weather	14°C (57°F)	121 mm (4.8 inches)	76%	very high
June Weather	19°C (67°F)	109 mm (4.3 inches)	72%	very high
July Weather	22°C (72°F)	182 mm (7.1 inches)	66%	very high
August Weather	21°C (70°F)	143 mm (5.6 inches)	64%	very high
September Weather	17°C (63°F)	129 mm (5.1 inches)	72%	very high
October Weather	11°C (53°F)	174 mm (6.9 inches)	81%	high
November Weather	4°C (39°F)	106 mm (4.2 inches)	87%	moderate
December Weather	-1°C (30°F)	130 mm (5.1 inches)	84%	low