Downs, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 41.5 °F (low) to 61.3 °F (high). Annual precipitation averages 39.1 Inches. Downs is located in USDA Plant Hardiness Zone 6a. 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 | 16.4 °F | 32.5 °F | 2.23 in. |
| February | 19.9 °F | 37.4 °F | 1.96 in. |
| March | 29.1 °F | 49.2 °F | 2.67 in. |
| April | 40.2 °F | 62.4 °F | 3.81 in. |
| May | 51.9 °F | 73.2 °F | 4.4 in. |
| June | 61.4 °F | 82.0 °F | 4.36 in. |
| July | 64.6 °F | 85.0 °F | 4.07 in. |
| August | 62.4 °F | 83.1 °F | 3.65 in. |
| September | 54.7 °F | 78.1 °F | 3.39 in. |
| October | 43.1 °F | 65.1 °F | 3.41 in. |
| November | 31.7 °F | 50.3 °F | 2.81 in. |
| December | 22.2 °F | 37.6 °F | 2.34 in. |
| Annual | 41.5 °F | 61.3 °F | 39.1 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 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 |