May Weather in Boise, United States

Last updated: June 24, 2025

In May, the average temperature in Boise, United States is a comfortable 16°C (61°F). However, be prepared for a range of conditions, as temperatures can dip to a chilly -2°C (29°F) or soar to a balmy 36°C (97°F). You can expect about 39 mm (1.5 in) of precipitation spread over roughly 6 days throughout the month, with an average humidity level of 71%.

May Temperature in Boise

In May in Boise, the average temperature is 16°C (61°F). Maximums can reach 36°C (97°F), while minimums can plummet to -2°C (29°F). Be prepared for a wide range of temperatures to ensure a comfortable trip.

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

The chart illustrates May temperature patterns in Boise, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Boise, May typically has an average temperature of 16°C (61°F), with highs reaching up to 36°C (97°F) and lows dropping to around -2°C (29°F).

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

May Precipitation in Boise

In Boise in May, the precipitation amount is 39 mm (1.5 in), occurring over the course of 6 days.

May Precipitation Trends in Boise

The chart displays monthly precipitation patterns in Boise, 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 Boise, May typically receives around 39 mm (1.5 inches) of precipitation spread over approximately 6 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 Boise

In Boise in May humidity is 71%. With an average temperature of 16°C (61°F), this humidity feels like walking through a warm, damp blanket, making travel slightly uncomfortable but still enjoyable for those who appreciate mild weather.

May Average Humidity in Boise

This chart illustrates the average monthly humidity levels in Boise, 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 Boise is approximately 71%, 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 Boise

In Boise 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 Boise.

Maximum UV Index Levels in Boise for May

The chart shows the monthly maximum UV Index (UVI) for Boise 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 Boise typically reaches 10, which falls under the very high exposure category.

Data source: Boise 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 Boise Compares to Other Months

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

This table compares monthly weather conditions in Boise, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	1°C (33°F)	49 mm (1.9 inches)	88%	moderate
February Weather	2°C (36°F)	50 mm (2.0 inches)	89%	moderate
March Weather	8°C (46°F)	38 mm (1.5 inches)	85%	high
April Weather	11°C (52°F)	36 mm (1.4 inches)	79%	very high
May Weather	16°C (61°F)	39 mm (1.5 inches)	71%	very high
June Weather	21°C (71°F)	21 mm (0.8 inches)	71%	extreme
July Weather	27°C (81°F)	1 mm (0.0 inches)	66%	extreme
August Weather	26°C (78°F)	8 mm (0.3 inches)	50%	very high
September Weather	20°C (68°F)	10 mm (0.4 inches)	48%	very high
October Weather	11°C (53°F)	22 mm (0.9 inches)	65%	high
November Weather	6°C (43°F)	32 mm (1.3 inches)	84%	moderate
December Weather	1°C (34°F)	40 mm (1.6 inches)	87%	low