Nebo, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.5 °C (low) to 17.9 °C (high). Annual precipitation averages 993.9 Millimeters. 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 | -6.9 °C | 2.6 °C | 53.85 mm |
| February | -5 °C | 5.4 °C | 49.78 mm |
| March | 0.1 °C | 11.6 °C | 71.12 mm |
| April | 5.9 °C | 18.5 °C | 102.62 mm |
| May | 12.2 °C | 23.8 °C | 115.57 mm |
| June | 17.2 °C | 28.8 °C | 115.32 mm |
| July | 19.3 °C | 30.7 °C | 102.11 mm |
| August | 18 °C | 30.1 °C | 88.65 mm |
| September | 13.3 °C | 26.6 °C | 89.41 mm |
| October | 7 °C | 19.7 °C | 74.68 mm |
| November | 1 °C | 11.9 °C | 75.69 mm |
| December | -4.2 °C | 5.2 °C | 55.12 mm |
| Annual | 6.5 °C | 17.9 °C | 993.92 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 |