Troy Grove, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 40 °F (low) to 60.1 °F (high). Annual precipitation averages 37.6 Inches. Troy Grove is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 14.5 °F | 30.8 °F | 1.78 in. |
| February | 18.3 °F | 35.3 °F | 1.73 in. |
| March | 27.9 °F | 47.7 °F | 2.38 in. |
| April | 38.4 °F | 61.1 °F | 3.58 in. |
| May | 50.1 °F | 72.5 °F | 4.61 in. |
| June | 59.9 °F | 81.2 °F | 4.68 in. |
| July | 63.4 °F | 84.1 °F | 4.08 in. |
| August | 61.3 °F | 82.3 °F | 3.86 in. |
| September | 53.3 °F | 76.9 °F | 3.44 in. |
| October | 41.6 °F | 64.2 °F | 3.02 in. |
| November | 30.7 °F | 48.9 °F | 2.47 in. |
| December | 20.5 °F | 36.0 °F | 1.98 in. |
| Annual | 40 °F | 60.1 °F | 37.61 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| 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 |