Crest Hill, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 40.9 °F (low) to 60.1 °F (high). Annual precipitation averages 39.9 Inches. Crest Hill is located in USDA Plant Hardiness Zone 6a. 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 | 16.3 °F | 31.6 °F | 2.11 in. |
| February | 19.0 °F | 35.6 °F | 1.95 in. |
| March | 28.6 °F | 47.4 °F | 2.5 in. |
| April | 39.0 °F | 60.5 °F | 3.93 in. |
| May | 49.9 °F | 71.4 °F | 4.82 in. |
| June | 59.9 °F | 80.8 °F | 4.7 in. |
| July | 63.9 °F | 84.4 °F | 4.32 in. |
| August | 62.5 °F | 82.6 °F | 4.21 in. |
| September | 54.9 °F | 76.9 °F | 3.37 in. |
| October | 42.7 °F | 63.7 °F | 3.39 in. |
| November | 31.8 °F | 49.2 °F | 2.46 in. |
| December | 22.0 °F | 36.8 °F | 2.17 in. |
| Annual | 40.9 °F | 60.1 °F | 39.93 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°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 |