May Weather in Umatilla, United States

Last updated: June 24, 2025

In May, the average temperature in Umatilla, United States hovers around 18°C (65°F), with a range between a brisk 2°C (35°F) and a sweltering 37°C (98°F). Expect 15 mm (0.6 in) of rainfall spread over 3 days, contributing to an average humidity level of 77%. Whether you're basking in the warmth or seeking shelter from the occasional rain, this month offers a dynamic climate.

May Temperature in Umatilla

In May in Umatilla, the average temperature is 18°C (65°F). Maximum temperatures can reach 37°C (98°F), while minimums can drop as low as 2°C (35°F). Be prepared for a wide range of temperatures when traveling during this month.

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

The chart illustrates May temperature patterns in Umatilla, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Umatilla, May typically has an average temperature of 18°C (65°F), with highs reaching up to 37°C (98°F) and lows dropping to around 2°C (35°F).

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

May Precipitation in Umatilla

In Umatilla in May, the precipitation amount is 15 mm (0.6 in) over the course of 3 days.

May Precipitation Trends in Umatilla

The chart displays monthly precipitation patterns in Umatilla, 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 Umatilla, May typically receives around 15 mm (0.6 inches) of precipitation spread over approximately 3 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 Umatilla

In Umatilla in May humidity is 77%. With an average temperature of 18°C (65°F), this humidity feels like a warm embrace that's both refreshing and slightly stifling, making it essential for travelers to stay hydrated and take frequent breaks to enjoy the vibrant surroundings without feeling overly fatigued.

May Average Humidity in Umatilla

This chart illustrates the average monthly humidity levels in Umatilla, 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 Umatilla is approximately 77%, 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 Umatilla

In Umatilla 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 Umatilla.

Maximum UV Index Levels in Umatilla for May

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

Data source: Umatilla 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 Umatilla Compares to Other Months

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

This table compares monthly weather conditions in Umatilla, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	2°C (36°F)	35 mm (1.4 inches)	86%	low
February Weather	3°C (37°F)	46 mm (1.8 inches)	86%	moderate
March Weather	8°C (46°F)	30 mm (1.2 inches)	85%	moderate
April Weather	13°C (55°F)	24 mm (0.9 inches)	83%	high
May Weather	18°C (65°F)	15 mm (0.6 inches)	77%	very high
June Weather	23°C (73°F)	8 mm (0.3 inches)	81%	very high
July Weather	27°C (81°F)	0 mm (0.0 inches)	76%	very high
August Weather	26°C (79°F)	4 mm (0.1 inches)	60%	very high
September Weather	20°C (69°F)	9 mm (0.4 inches)	58%	high
October Weather	12°C (54°F)	26 mm (1.0 inches)	75%	moderate
November Weather	6°C (43°F)	34 mm (1.3 inches)	85%	moderate
December Weather	2°C (37°F)	33 mm (1.3 inches)	87%	low