Fulton, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.3 °C (low) to 15.2 °C (high). Annual precipitation averages 941.1 Millimeters. Fulton is located in USDA Plant Hardiness Zone 5b. 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 | -10.6 °C | -1.4 °C | 38.86 mm |
| February | -8.4 °C | 1.2 °C | 44.2 mm |
| March | -2.4 °C | 8.2 °C | 63.25 mm |
| April | 3.7 °C | 15.7 °C | 90.42 mm |
| May | 10.2 °C | 22 °C | 112.52 mm |
| June | 15.8 °C | 27.2 °C | 128.02 mm |
| July | 17.7 °C | 28.8 °C | 100.08 mm |
| August | 16.4 °C | 27.8 °C | 96.77 mm |
| September | 11.8 °C | 24.4 °C | 92.46 mm |
| October | 5.3 °C | 17.3 °C | 68.58 mm |
| November | -1.1 °C | 8.9 °C | 58.17 mm |
| December | -6.9 °C | 1.7 °C | 47.75 mm |
| Annual | 4.3 °C | 15.2 °C | 941.08 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |