August Weather in Grinnell, United States

Last updated: June 24, 2025

In August, the average temperature in Grinnell, United States is a comfortable 23°C (73°F). However, be prepared for a range with minimums dipping to 11°C (51°F) and maximums soaring to 34°C (94°F). Rain may grace the area with an average precipitation of 71 mm (2.8 in) spread over 9 days. Expect a relatively high average humidity of 77%, making it feel a bit more tropical!

August Temperature in Grinnell

In August, in Grinnell, the average temperature is 23°C (73°F), with maximums reaching up to 34°C (94°F) and minimums dipping as low as 11°C (51°F). This pleasant climate makes Grinnell a wonderful destination for travelers seeking a comfortable getaway.

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

The chart illustrates August 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, August typically has an average temperature of 23°C (73°F), with highs reaching up to 34°C (94°F) and lows dropping to around 11°C (51°F).

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

August Precipitation in Grinnell

In Grinnell in August, the precipitation amount is 71 mm (2.8 in) spread over 9 days.

August Precipitation Trends in Grinnell

The chart displays monthly precipitation patterns in Grinnell, with values for each month alongside August’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how August’s conditions compare to those of other months. In Grinnell, August typically receives around 71 mm (2.8 inches) of precipitation spread over approximately 9 days.

Data source: Precipitation data for August generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

August Humidity in Grinnell

In Grinnell in August, humidity is 77%. With an average temperature of 23°C (73°F), this humidity feels like a warm, sticky embrace, making travel somewhat uncomfortable but bearable. It's essential to stay hydrated and take frequent breaks to enjoy the sights while avoiding overheating.

August Average Humidity in Grinnell

This chart illustrates the average monthly humidity levels in Grinnell, with August’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In August, average humidity in Grinnell is approximately 77%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for August generated using information from the Copernicus Climate Change Service.

August UV Index in Grinnell

In Grinnell in August, 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 August

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

Data source: Grinnell August 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 August 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 August’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 August’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