May Weather in Washington, United States

Last updated: June 24, 2025

In May, the average temperature in Washington, United States is a mild 14°C (57°F). However, temperatures can vary significantly, with a minimum of -1°C (31°F) and a maximum of 32°C (90°F). You can expect 121 mm (4.8 in) of precipitation spread over 14 days, resulting in an average humidity of 76%. Whether you're packing for warmth or a light drizzle, be prepared for diverse weather conditions!

May Temperature in Washington

In May in Washington, the average temperature is 14°C (57°F). Maximums can reach 32°C (90°F), while minimums can drop as low as -1°C (31°F). Travelers should be prepared for a range of temperatures, so packing layers is advisable.

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 14°C (57°F), with highs reaching up to 32°C (90°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 121 mm (4.8 in) over a span of 14 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 121 mm (4.8 inches) of precipitation spread over approximately 14 days.

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

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

May Humidity in Washington

In Washington in May humidity is 76%. With an average temperature of 14°C (57°F), this humidity feels like a warm blanket wrapped around you, creating a heavy atmosphere that can make outdoor activities feel sluggish and stifling, urging travelers to seek shade and refreshment more frequently.

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 76%, 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 reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. For more 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 10, 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	-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