May Weather in Grinnell, United States

Last updated: June 24, 2025

The average temperature in Grinnell, United States during May hovers around 17°C (62°F), with fluctuations that can bring the minimum down to 0°C (32°F) and peak as high as 35°C (95°F). Expect approximately 166 mm (6.5 in) of precipitation spread across 15 days, contributing to a 77% average humidity that enhances the area's vibrant atmosphere.

May Temperature in Grinnell

In May in Grinnell, the average temperature is 17°C (62°F), with maximums reaching 35°C (95°F) and minimums dropping as low as 0°C (32°F). Travelers should pack accordingly to enjoy the diverse climate during their visit.

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

The chart illustrates May temperature patterns in Grinnell, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Grinnell, May typically has an average temperature of 17°C (62°F), with highs reaching up to 35°C (95°F) and lows dropping to around 0°C (32°F).

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

May Precipitation in Grinnell

In Grinnell in May, the total precipitation amount is 166 mm (6.5 in) spread across 15 days.

May Precipitation Trends in Grinnell

The chart displays monthly precipitation patterns in Grinnell, 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 Grinnell, May typically receives around 166 mm (6.5 inches) of precipitation spread over approximately 15 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 Grinnell

In Grinnell in May humidity is 77%. With an average temperature of 17°C (62°F), this humidity feels like a warm embrace, creating a lush, almost tropical atmosphere that can be quite stifling for traveling, making it essential to stay hydrated and take frequent breaks in the shade.

May Average Humidity in Grinnell

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

In Grinnell 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 Grinnell.

Maximum UV Index Levels in Grinnell for May

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

Data source: Grinnell 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 Grinnell Compares to Other Months

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

This table compares monthly weather conditions in Grinnell, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-6°C (22°F)	43 mm (1.7 inches)	78%	moderate
February Weather	-5°C (23°F)	48 mm (1.9 inches)	80%	moderate
March Weather	4°C (39°F)	79 mm (3.1 inches)	77%	high
April Weather	9°C (49°F)	81 mm (3.2 inches)	77%	very high
May Weather	17°C (62°F)	166 mm (6.5 inches)	77%	very high
June Weather	23°C (74°F)	133 mm (5.2 inches)	81%	extreme
July Weather	24°C (76°F)	81 mm (3.2 inches)	81%	very high
August Weather	23°C (73°F)	71 mm (2.8 inches)	77%	very high
September Weather	20°C (68°F)	118 mm (4.7 inches)	73%	very high
October Weather	11°C (53°F)	145 mm (5.7 inches)	75%	high
November Weather	3°C (38°F)	46 mm (1.8 inches)	85%	moderate
December Weather	-1°C (31°F)	38 mm (1.5 inches)	83%	moderate