Grinnell (IA) Weather & Climate: Best Time to Visit
Average temperatures, rainfall, sunshine and the best time to visit Grinnell.
Climate overview of Grinnell
The climate in Grinnell, Iowa, United States of America, is marked by large temperature swings across the seasons, ranging from 29°C (84°F) in July to -2°C (28°F) in January.
Rain/snowfall is high, totalling around 1041 mm (41 in) per year. June is the wettest month and January the driest. The city also experiences warm summers and very cold winters.
Grinnell Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in Grinnell - and find the best time to visit.
Monthly Temperature in Grinnell
In Grinnell, temperatures differ significantly between summer and winter months. Average maximum daytime temperatures range from a comfortable 29°C (84°F) in July, the warmest time of the year, to a very cold -2°C (28°F) during cooler months like January.
At night, you can expect temperatures ranging from 18°C (64°F) in July to around -12°C (10°F) during January.
Check out our detailed temperature page for more information.
Temperature ranges by month
Rainfall in Grinnell
Grinnell experiences significant rain/snowfall throughout the year, averaging 1041 mm (41 in) of precipitation annually. Significant seasonal changes in precipitation occur throughout the year. In the wettest month, June it receives high rainfall, averaging 158 mm (6.2 in) of precipitation, recorded across 13 rainy days. In contrast, the driest month January brings less snowfall, with 22 mm (0.9 in) over 7 snowy days. For more details, please visit our Grinnell Precipitation page.
The mean monthly precipitation over the year, including rain, hail, and snow
The average number of days each month with precipitation
Best Time to Visit Grinnell
Monthly ratings reflect general weather comfort, based on daytime temperature and rainfall. Swimming and winter conditions are highlighted separately where relevant.
- Best overall: September
- Warmest weather: July and August
- Fewest rainy days: January, February, March and November
- Wettest months: April, May, June, July, August and September, when rainfall is highest.
- Seasonal pattern: Warm summers and very cold winters
- Coldest conditions: January, with freezing nights around -12°C (10°F).
Frequently asked questions about the climate in Grinnell
What is the best time to visit Grinnell?
September typically offers the most optimal weather in Grinnell. In contrast, January, February, March, November and December tend to have less optimal conditions. Grinnell has warm summers and very cold winters.
What temperatures can I expect in Grinnell?
Daytime highs range from -2°C (28°F) in January to 29°C (84°F) in July. Nighttime lows range from -12°C (10°F) to 18°C (64°F). Temperatures vary considerably through the year.
How much rain does Grinnell get?
Annual rainfall is around 1041 mm (41 in). June is the wettest month with 158 mm (6.2 in), while January is the driest with 22 mm (0.9 in).
Grinnell 3-Day Forecast
Grinnell (IA) 3-Day Forecast
Grinnell on the map
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