Greenup, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 44.2 °F (low) to 64.7 °F (high). Annual precipitation averages 44.1 Inches. Greenup is located in USDA Plant Hardiness Zone 6b. 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 | 21.3 °F | 37.3 °F | 3.0 in. |
| February | 24.1 °F | 42.1 °F | 2.53 in. |
| March | 33.2 °F | 53.2 °F | 3.34 in. |
| April | 43.6 °F | 66.2 °F | 4.79 in. |
| May | 54.4 °F | 75.6 °F | 4.82 in. |
| June | 63.1 °F | 83.9 °F | 4.95 in. |
| July | 66.0 °F | 87.3 °F | 4.24 in. |
| August | 63.9 °F | 86.1 °F | 3.01 in. |
| September | 56.0 °F | 80.7 °F | 3.23 in. |
| October | 44.8 °F | 68.6 °F | 3.6 in. |
| November | 34.4 °F | 53.7 °F | 3.74 in. |
| December | 26.1 °F | 41.7 °F | 2.84 in. |
| Annual | 44.2 °F | 64.7 °F | 44.09 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 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |