Fulton, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 39.7 °F (low) to 59.3 °F (high). Annual precipitation averages 37.1 Inches. 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 | 13.0 °F | 29.5 °F | 1.53 in. |
| February | 16.8 °F | 34.1 °F | 1.74 in. |
| March | 27.6 °F | 46.7 °F | 2.49 in. |
| April | 38.6 °F | 60.2 °F | 3.56 in. |
| May | 50.3 °F | 71.6 °F | 4.43 in. |
| June | 60.4 °F | 80.9 °F | 5.04 in. |
| July | 63.8 °F | 83.9 °F | 3.94 in. |
| August | 61.6 °F | 82.1 °F | 3.81 in. |
| September | 53.3 °F | 76.0 °F | 3.64 in. |
| October | 41.6 °F | 63.1 °F | 2.7 in. |
| November | 30.0 °F | 48.0 °F | 2.29 in. |
| December | 19.5 °F | 35.1 °F | 1.88 in. |
| Annual | 39.7 °F | 59.3 °F | 37.05 in. |
| 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 : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |