Nebo, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 43.7 °F (low) to 64.2 °F (high). Annual precipitation averages 39.1 Inches. Nebo 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 | 19.5 °F | 36.6 °F | 2.12 in. |
| February | 23.0 °F | 41.8 °F | 1.96 in. |
| March | 32.1 °F | 52.8 °F | 2.8 in. |
| April | 42.7 °F | 65.3 °F | 4.04 in. |
| May | 53.9 °F | 74.8 °F | 4.55 in. |
| June | 63.0 °F | 83.8 °F | 4.54 in. |
| July | 66.7 °F | 87.3 °F | 4.02 in. |
| August | 64.4 °F | 86.1 °F | 3.49 in. |
| September | 55.9 °F | 79.8 °F | 3.52 in. |
| October | 44.6 °F | 67.5 °F | 2.94 in. |
| November | 33.8 °F | 53.4 °F | 2.98 in. |
| December | 24.5 °F | 41.3 °F | 2.17 in. |
| Annual | 43.7 °F | 64.2 °F | 39.13 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 |