May Weather in Washington, United States

Last updated: June 24, 2025

In May, the average temperature in Washington, United States hovers around 7°C (45°F), providing a crisp atmosphere. Expect a minimum of -1°C (31°F) and a maximum of 17°C (62°F), making it a month of contrast. With an average precipitation of 83 mm (3.3 in) over about 9 days, be prepared for occasional showers. The air carries an average humidity of 82%, adding a fresh feel to the scenery.

May Temperature in Washington

In May in Washington, the average temperature is 7°C (45°F). Maximums can reach 17°C (62°F) and minimums can drop as low as -1°C (31°F). It's advisable to pack layers for your travels to Washington during this time to ensure comfort in varying temperatures.

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

The chart illustrates May 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, May typically has an average temperature of 7°C (45°F), with highs reaching up to 17°C (62°F) and lows dropping to around -1°C (31°F).

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

May Precipitation in Washington

In Washington in May, the precipitation amount is 83 mm (3.3 in) over the course of 9 days.

May Precipitation Trends in Washington

The chart displays monthly precipitation patterns in Washington, with values for each month alongside May’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how May’s conditions compare to those of other months. In Washington, May typically receives around 83 mm (3.3 inches) of precipitation spread over approximately 9 days.

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

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Millimeters (mm) Inches (in)

May Humidity in Washington

In Washington in May humidity is 82%. With an average temperature of 7°C (45°F), this humidity feels like a damp chill that seeps into your bones, making outdoor activities feel much colder and less inviting, which can make exploring less enjoyable unless you're dressed warmly.

May Average Humidity in Washington

This chart illustrates the average monthly humidity levels in Washington, with May’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In May, average humidity in Washington is approximately 82%, offering insight into how humid the weather typically is during this month.

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

May UV Index in Washington

In Washington in May, 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 May

The chart shows the monthly maximum UV Index (UVI) for Washington in May, 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 May, the maximum UV index in Washington typically reaches 9, which falls under the very high exposure category.

Data source: Washington May 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 May 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 May’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 May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-5°C (24°F)	44 mm (1.7 inches)	91%	low
February Weather	-5°C (23°F)	56 mm (2.2 inches)	91%	moderate
March Weather	-1°C (30°F)	61 mm (2.4 inches)	87%	moderate
April Weather	2°C (36°F)	90 mm (3.5 inches)	87%	high
May Weather	7°C (45°F)	83 mm (3.3 inches)	82%	very high
June Weather	14°C (57°F)	90 mm (3.5 inches)	79%	very high
July Weather	20°C (68°F)	76 mm (3.0 inches)	75%	very high
August Weather	20°C (68°F)	87 mm (3.4 inches)	76%	very high
September Weather	17°C (62°F)	85 mm (3.4 inches)	79%	high
October Weather	11°C (51°F)	114 mm (4.5 inches)	83%	moderate
November Weather	3°C (38°F)	67 mm (2.6 inches)	86%	moderate
December Weather	-1°C (30°F)	70 mm (2.8 inches)	87%	low