May Weather in Washington, United States

Last updated: June 24, 2025

In May, the average temperature in Washington, United States is a pleasant 21°C (71°F). You can expect a minimum temperature of 4°C (40°F) and a maximum hot streak reaching 36°C (97°F). While enjoying the warmth, be prepared for 118 mm (4.6 in) of precipitation over 11 days, with average humidity levels sitting at a high 81%. Make the most of your time in this vibrant locale!

May Temperature in Washington

In May in Washington, the average temperature is 21°C (71°F), with maximum temperatures potentially reaching 36°C (97°F) and minimum temperatures dipping as low as 4°C (40°F). This diverse climate makes Washington an ideal travel destination, offering pleasant warm days and cool evenings.

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 21°C (71°F), with highs reaching up to 36°C (97°F) and lows dropping to around 4°C (40°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 118 mm (4.6 in) over the course of 11 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 118 mm (4.6 inches) of precipitation spread over approximately 11 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 81%. With an average temperature of 21°C (71°F), this humidity feels like a warm, enveloping blanket that makes traveling feel both refreshing and slightly heavy, often leading to a sticky sensation that can quickly deplete your energy.

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 81%, 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 11, which corresponds to an extreme Exposure Category. With a time to burn of just 10 minutes, it's essential to take precautions. For more details, 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 11, which falls under the extreme 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	7°C (45°F)	85 mm (3.4 inches)	84%	moderate
February Weather	10°C (50°F)	90 mm (3.5 inches)	81%	high
March Weather	12°C (54°F)	68 mm (2.7 inches)	80%	very high
April Weather	17°C (63°F)	103 mm (4.1 inches)	80%	very high
May Weather	21°C (71°F)	118 mm (4.6 inches)	81%	extreme
June Weather	25°C (77°F)	152 mm (6.0 inches)	82%	extreme
July Weather	27°C (80°F)	159 mm (6.3 inches)	83%	extreme
August Weather	26°C (79°F)	182 mm (7.2 inches)	82%	very high
September Weather	24°C (75°F)	147 mm (5.8 inches)	80%	very high
October Weather	19°C (67°F)	72 mm (2.8 inches)	79%	very high
November Weather	12°C (54°F)	97 mm (3.8 inches)	83%	moderate
December Weather	9°C (49°F)	108 mm (4.3 inches)	84%	moderate