Heritage Lake, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 41.1 °F (low) to 61.9 °F (high). Annual precipitation averages 38.7 Inches. Heritage Lake 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 | 16.2 °F | 32.9 °F | 2.21 in. |
| February | 19.5 °F | 37.8 °F | 1.94 in. |
| March | 29.1 °F | 49.9 °F | 2.58 in. |
| April | 39.9 °F | 63.1 °F | 3.8 in. |
| May | 51.4 °F | 73.6 °F | 4.7 in. |
| June | 61.0 °F | 82.3 °F | 4.26 in. |
| July | 64.3 °F | 85.5 °F | 3.94 in. |
| August | 62.1 °F | 83.9 °F | 3.65 in. |
| September | 54.1 °F | 79.2 °F | 3.3 in. |
| October | 42.5 °F | 65.9 °F | 3.11 in. |
| November | 31.4 °F | 50.9 °F | 2.93 in. |
| December | 21.8 °F | 38.1 °F | 2.25 in. |
| Annual | 41.1 °F | 61.9 °F | 38.67 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 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |