Mounds, Illinois has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 48 °F (low) to 68.2 °F (high). Annual precipitation averages 50.1 Inches. Mounds is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 26.7 °F | 43.3 °F | 3.84 in. |
| February | 29.7 °F | 48.4 °F | 3.78 in. |
| March | 37.6 °F | 58.0 °F | 4.82 in. |
| April | 47.6 °F | 69.2 °F | 5.34 in. |
| May | 57.8 °F | 78.2 °F | 5.25 in. |
| June | 66.2 °F | 86.4 °F | 4.32 in. |
| July | 69.6 °F | 89.0 °F | 3.85 in. |
| August | 67.0 °F | 87.7 °F | 2.9 in. |
| September | 58.9 °F | 82.0 °F | 3.43 in. |
| October | 47.2 °F | 71.5 °F | 3.92 in. |
| November | 37.2 °F | 57.8 °F | 4.4 in. |
| December | 30.2 °F | 46.8 °F | 4.25 in. |
| Annual | 48 °F | 68.2 °F | 50.1 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 7a : 0°F to 5°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |