August Weather in Washington, United States

Last updated: June 24, 2025

In Washington, United States, the average temperature in August hovers around 21°C (70°F), but be prepared for fluctuations—minimums can plunge to 8°C (46°F), while maximums can soar to 35°C (95°F). During this month, expect about 94 mm (3.7 in) of precipitation over 10 days, contributing to an average humidity level of 66%.

August Temperature in Washington

In August in Washington, the average temperature is 21°C (70°F). Maximum can reach 35°C (95°F) and minimum can be as low as 8°C (46°F). This range makes Washington an ideal destination for travelers seeking both warm days and cool evenings.

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 35°C (95°F) and lows dropping to around 8°C (46°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 94 mm (3.7 in) over a duration of 10 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 94 mm (3.7 inches) of precipitation spread over approximately 10 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 66%. With an average temperature of 21°C (70°F), this humidity feels like a warm embrace, making it comfortable for leisurely strolls but slightly sticky for longer excursions.

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 66%, 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	-5°C (23°F)	71 mm (2.8 inches)	86%	moderate
February Weather	-3°C (26°F)	85 mm (3.3 inches)	84%	moderate
March Weather	0°C (32°F)	78 mm (3.1 inches)	82%	high
April Weather	7°C (44°F)	126 mm (5.0 inches)	80%	very high
May Weather	13°C (56°F)	83 mm (3.3 inches)	72%	very high
June Weather	19°C (66°F)	90 mm (3.5 inches)	72%	very high
July Weather	22°C (72°F)	129 mm (5.1 inches)	67%	very high
August Weather	21°C (70°F)	94 mm (3.7 inches)	66%	very high
September Weather	17°C (63°F)	78 mm (3.1 inches)	71%	high
October Weather	10°C (51°F)	132 mm (5.2 inches)	78%	high
November Weather	3°C (37°F)	105 mm (4.1 inches)	84%	moderate
December Weather	-3°C (27°F)	114 mm (4.5 inches)	81%	low