Deer Grove, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.3 °C (low) to 15.3 °C (high). Annual precipitation averages 968.2 Millimeters. Deer Grove is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.2 °C | -1.2 °C | 43.69 mm |
| February | -8.1 °C | 1.3 °C | 43.43 mm |
| March | -2.4 °C | 8.3 °C | 60.71 mm |
| April | 3.6 °C | 15.9 °C | 91.69 mm |
| May | 10.2 °C | 22.2 °C | 122.43 mm |
| June | 15.7 °C | 27.2 °C | 129.54 mm |
| July | 17.5 °C | 28.8 °C | 103.38 mm |
| August | 16.3 °C | 27.8 °C | 103.12 mm |
| September | 11.7 °C | 24.6 °C | 87.88 mm |
| October | 5.2 °C | 17.6 °C | 75.18 mm |
| November | -1.1 °C | 9 °C | 58.67 mm |
| December | -6.7 °C | 1.9 °C | 48.51 mm |
| Annual | 4.3 °C | 15.3 °C | 968.23 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |