Leonore, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 40.8 °F (low) to 60.7 °F (high). Annual precipitation averages 37.3 Inches. Leonore 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 | 15.7 °F | 31.5 °F | 1.9 in. |
| February | 19.2 °F | 36.0 °F | 1.79 in. |
| March | 28.8 °F | 48.4 °F | 2.47 in. |
| April | 39.2 °F | 61.8 °F | 3.55 in. |
| May | 51.1 °F | 72.9 °F | 4.6 in. |
| June | 60.7 °F | 81.7 °F | 4.37 in. |
| July | 64.2 °F | 84.5 °F | 3.87 in. |
| August | 62.1 °F | 82.7 °F | 3.7 in. |
| September | 53.9 °F | 77.5 °F | 3.39 in. |
| October | 42.2 °F | 64.9 °F | 3.01 in. |
| November | 31.3 °F | 49.5 °F | 2.57 in. |
| December | 21.5 °F | 36.8 °F | 2.04 in. |
| Annual | 40.8 °F | 60.7 °F | 37.26 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 | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |