Annual Weather Averages Near Grinnell
Averages are for Newton Municipal, which is 16 miles from Grinnell.
Based on weather reports collected during 1992–2021.
All Year Climate & Weather Averages in Grinnell
High Temp: 85 °F
Low Temp: 12 °F
Mean Temp: 49 °F
Precipitation: 2.91"
Humidity: 73%
Dew Point: 41 °F
Wind: 17 mph
Pressure: 30.02 "Hg
Visibility: 9 mi
January Climate & Weather Averages in Grinnell
High Temp: 29 °F
Low Temp: 12 °F
Mean Temp: 20 °F
Precipitation: 0.93"
Humidity: 78%
Dew Point: 17 °F
Wind: 18 mph
Pressure: 30.10 "Hg
Visibility: 8 mi
February Climate & Weather Averages in Grinnell
High Temp: 33 °F
Low Temp: 15 °F
Mean Temp: 24 °F
Precipitation: 1.12"
Humidity: 76%
Dew Point: 20 °F
Wind: 18 mph
Pressure: 30.09 "Hg
Visibility: 8 mi
March Climate & Weather Averages in Grinnell
High Temp: 47 °F
Low Temp: 27 °F
Mean Temp: 37 °F
Precipitation: 1.97"
Humidity: 71%
Dew Point: 29 °F
Wind: 20 mph
Pressure: 30.05 "Hg
Visibility: 9 mi
April Climate & Weather Averages in Grinnell
High Temp: 61 °F
Low Temp: 38 °F
Mean Temp: 49 °F
Precipitation: 3.40"
Humidity: 65%
Dew Point: 38 °F
Wind: 21 mph
Pressure: 29.94 "Hg
Visibility: 9 mi
May Climate & Weather Averages in Grinnell
High Temp: 72 °F
Low Temp: 50 °F
Mean Temp: 61 °F
Precipitation: 4.82"
Humidity: 68%
Dew Point: 50 °F
Wind: 18 mph
Pressure: 29.95 "Hg
Visibility: 9 mi
June Climate & Weather Averages in Grinnell
High Temp: 82 °F
Low Temp: 60 °F
Mean Temp: 71 °F
Precipitation: 5.02"
Humidity: 72%
Dew Point: 61 °F
Wind: 15 mph
Pressure: 29.93 "Hg
Visibility: 9 mi
July Climate & Weather Averages in Grinnell
High Temp: 85 °F
Low Temp: 64 °F
Mean Temp: 75 °F
Precipitation: 4.05"
Humidity: 76%
Dew Point: 66 °F
Wind: 12 mph
Pressure: 29.98 "Hg
Visibility: 9 mi
August Climate & Weather Averages in Grinnell
High Temp: 83 °F
Low Temp: 62 °F
Mean Temp: 72 °F
Precipitation: 4.27"
Humidity: 76%
Dew Point: 64 °F
Wind: 12 mph
Pressure: 30.00 "Hg
Visibility: 9 mi
September Climate & Weather Averages in Grinnell
High Temp: 77 °F
Low Temp: 53 °F
Mean Temp: 65 °F
Precipitation: 3.57"
Humidity: 71%
Dew Point: 54 °F
Wind: 14 mph
Pressure: 30.03 "Hg
Visibility: 9 mi
October Climate & Weather Averages in Grinnell
High Temp: 63 °F
Low Temp: 41 °F
Mean Temp: 52 °F
Precipitation: 2.72"
Humidity: 69%
Dew Point: 41 °F
Wind: 17 mph
Pressure: 30.03 "Hg
Visibility: 9 mi
November Climate & Weather Averages in Grinnell
High Temp: 48 °F
Low Temp: 28 °F
Mean Temp: 38 °F
Precipitation: 1.86"
Humidity: 73%
Dew Point: 30 °F
Wind: 18 mph
Pressure: 30.06 "Hg
Visibility: 9 mi
December Climate & Weather Averages in Grinnell
High Temp: 35 °F
Low Temp: 18 °F
Mean Temp: 26 °F
Precipitation: 1.24"
Humidity: 79%
Dew Point: 22 °F
Wind: 18 mph
Pressure: 30.07 "Hg
Visibility: 8 mi