Hettick, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.3 °C (low) to 17.6 °C (high). Annual precipitation averages 1022.1 Millimeters. Hettick is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7 °C | 2.2 °C | 57.66 mm |
| February | -5 °C | 5.1 °C | 52.32 mm |
| March | -0.1 °C | 11.3 °C | 76.2 mm |
| April | 5.8 °C | 18.3 °C | 113.28 mm |
| May | 12.1 °C | 23.8 °C | 123.19 mm |
| June | 17.1 °C | 28.4 °C | 112.01 mm |
| July | 18.9 °C | 30.1 °C | 94.49 mm |
| August | 17.6 °C | 29.6 °C | 85.09 mm |
| September | 12.9 °C | 26.4 °C | 83.31 mm |
| October | 6.6 °C | 19.7 °C | 82.3 mm |
| November | 0.8 °C | 11.6 °C | 83.31 mm |
| December | -4.2 °C | 4.9 °C | 58.93 mm |
| Annual | 6.3 °C | 17.6 °C | 1022.09 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |