Deer Grove, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 39.7 °F (low) to 59.5 °F (high). Annual precipitation averages 38.1 Inches. 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 | 13.6 °F | 29.9 °F | 1.72 in. |
| February | 17.4 °F | 34.4 °F | 1.71 in. |
| March | 27.6 °F | 46.9 °F | 2.39 in. |
| April | 38.5 °F | 60.7 °F | 3.61 in. |
| May | 50.4 °F | 71.9 °F | 4.82 in. |
| June | 60.2 °F | 80.9 °F | 5.1 in. |
| July | 63.5 °F | 83.8 °F | 4.07 in. |
| August | 61.3 °F | 82.1 °F | 4.06 in. |
| September | 53.0 °F | 76.3 °F | 3.46 in. |
| October | 41.4 °F | 63.7 °F | 2.96 in. |
| November | 30.0 °F | 48.2 °F | 2.31 in. |
| December | 19.9 °F | 35.4 °F | 1.91 in. |
| Annual | 39.7 °F | 59.5 °F | 38.12 in. |
| 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 : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |