Prairie City, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 41 °F (low) to 61.6 °F (high). Annual precipitation averages 38.1 Inches. Prairie City is located in USDA Plant Hardiness Zone 6a. 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 | 15.3 °F | 32.6 °F | 1.87 in. |
| February | 18.9 °F | 37.2 °F | 1.89 in. |
| March | 29.1 °F | 49.9 °F | 2.6 in. |
| April | 39.8 °F | 63.1 °F | 3.74 in. |
| May | 51.8 °F | 73.5 °F | 5.0 in. |
| June | 61.5 °F | 82.3 °F | 4.88 in. |
| July | 64.5 °F | 85.4 °F | 3.95 in. |
| August | 62.1 °F | 83.7 °F | 3.36 in. |
| September | 54.2 °F | 77.9 °F | 3.62 in. |
| October | 42.3 °F | 65.6 °F | 3.02 in. |
| November | 31.0 °F | 50.4 °F | 2.34 in. |
| December | 21.2 °F | 37.8 °F | 1.81 in. |
| Annual | 41 °F | 61.6 °F | 38.08 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 6a : -10°F to -5°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 |