Troy Grove, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.4 °C (low) to 15.6 °C (high). Annual precipitation averages 955.3 Millimeters. 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 | -9.7 °C | -0.7 °C | 45.21 mm |
| February | -7.6 °C | 1.8 °C | 43.94 mm |
| March | -2.3 °C | 8.7 °C | 60.45 mm |
| April | 3.6 °C | 16.2 °C | 90.93 mm |
| May | 10.1 °C | 22.5 °C | 117.09 mm |
| June | 15.5 °C | 27.3 °C | 118.87 mm |
| July | 17.4 °C | 28.9 °C | 103.63 mm |
| August | 16.3 °C | 27.9 °C | 98.04 mm |
| September | 11.8 °C | 24.9 °C | 87.38 mm |
| October | 5.3 °C | 17.9 °C | 76.71 mm |
| November | -0.7 °C | 9.4 °C | 62.74 mm |
| December | -6.4 °C | 2.2 °C | 50.29 mm |
| Annual | 4.4 °C | 15.6 °C | 955.28 mm |
| 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 : -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 |