May Weather in Northwest, United States

Last updated: June 24, 2025

In Northwest, United States, the average temperature in May is a pleasant 22°C (72°F). However, temperatures can vary significantly, with a minimum of 5°C (41°F) and a maximum reaching up to 36°C (98°F). Expect some rain, as 120 mm (4.7 in) of precipitation is likely over 11 days. Additionally, the average humidity is relatively high at 81%, creating a warm and humid environment.

May Temperature in Northwest

In May in Northwest, the average temperature is 22°C (72°F), with maximums reaching up to 36°C (98°F) and minimums dipping as low as 5°C (41°F). It's advisable to pack layers to ensure comfort during the warm days and cooler nights.

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

The chart illustrates May temperature patterns in Northwest, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Northwest, May typically has an average temperature of 22°C (72°F), with highs reaching up to 36°C (98°F) and lows dropping to around 5°C (41°F).

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

May Precipitation in Northwest

In Northwest in May, the precipitation amount is 120 mm (4.7 in) during a span of 11 days.

May Precipitation Trends in Northwest

The chart displays monthly precipitation patterns in Northwest, 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 Northwest, May typically receives around 120 mm (4.7 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 Northwest

In Northwest in May, humidity is 81%. With an average temperature of 22°C (72°F), this humidity feels like a warm, enveloping blanket, making traveling feel both lush and a bit stifling, as the air clings to your skin and every step is accompanied by a gentle sheen of moisture.

May Average Humidity in Northwest

This chart illustrates the average monthly humidity levels in Northwest, 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 Northwest 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 Northwest

In Northwest 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 Northwest.

Maximum UV Index Levels in Northwest for May

The chart shows the monthly maximum UV Index (UVI) for Northwest 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 Northwest typically reaches 11, which falls under the extreme exposure category.

Data source: Northwest 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 Northwest Compares to Other Months

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

This table compares monthly weather conditions in Northwest, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	9°C (48°F)	70 mm (2.8 inches)	85%	moderate
February Weather	12°C (53°F)	93 mm (3.7 inches)	82%	high
March Weather	13°C (56°F)	70 mm (2.8 inches)	81%	very high
April Weather	18°C (64°F)	94 mm (3.7 inches)	80%	very high
May Weather	22°C (72°F)	120 mm (4.7 inches)	81%	extreme
June Weather	25°C (77°F)	160 mm (6.3 inches)	81%	extreme
July Weather	27°C (80°F)	171 mm (6.7 inches)	81%	extreme
August Weather	26°C (80°F)	205 mm (8.1 inches)	80%	very high
September Weather	24°C (76°F)	193 mm (7.6 inches)	79%	very high
October Weather	20°C (69°F)	64 mm (2.5 inches)	80%	very high
November Weather	13°C (55°F)	110 mm (4.3 inches)	85%	high
December Weather	10°C (51°F)	124 mm (4.9 inches)	86%	moderate