Greenup, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.8 °C (low) to 18.2 °C (high). Annual precipitation averages 1119.9 Millimeters. 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 | -5.9 °C | 2.9 °C | 76.2 mm |
| February | -4.4 °C | 5.6 °C | 64.26 mm |
| March | 0.7 °C | 11.8 °C | 84.84 mm |
| April | 6.4 °C | 19 °C | 121.67 mm |
| May | 12.4 °C | 24.2 °C | 122.43 mm |
| June | 17.3 °C | 28.8 °C | 125.73 mm |
| July | 18.9 °C | 30.7 °C | 107.7 mm |
| August | 17.7 °C | 30.1 °C | 76.45 mm |
| September | 13.3 °C | 27.1 °C | 82.04 mm |
| October | 7.1 °C | 20.3 °C | 91.44 mm |
| November | 1.3 °C | 12.1 °C | 95 mm |
| December | -3.3 °C | 5.4 °C | 72.14 mm |
| Annual | 6.8 °C | 18.2 °C | 1119.9 mm |
| 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 : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |