Wonder Lake, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 38.3 °F (low) to 57.7 °F (high). Annual precipitation averages 38.2 Inches. Wonder Lake 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 | 13.5 °F | 29.1 °F | 1.78 in. |
| February | 16.3 °F | 33.0 °F | 1.87 in. |
| March | 25.6 °F | 44.5 °F | 2.22 in. |
| April | 36.1 °F | 57.5 °F | 3.82 in. |
| May | 47.2 °F | 69.1 °F | 4.57 in. |
| June | 57.1 °F | 78.8 °F | 4.94 in. |
| July | 61.6 °F | 82.8 °F | 3.87 in. |
| August | 59.9 °F | 81.0 °F | 3.89 in. |
| September | 52.0 °F | 74.4 °F | 3.61 in. |
| October | 40.6 °F | 61.2 °F | 3.12 in. |
| November | 29.9 °F | 46.8 °F | 2.45 in. |
| December | 19.5 °F | 34.3 °F | 2.01 in. |
| Annual | 38.3 °F | 57.7 °F | 38.15 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 | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |