Hainesville, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 39.2 °F (low) to 57.6 °F (high). Annual precipitation averages 38 Inches. Hainesville is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 14.3 °F | 29.6 °F | 1.92 in. |
| February | 17.1 °F | 33.4 °F | 1.96 in. |
| March | 26.5 °F | 44.5 °F | 2.29 in. |
| April | 36.8 °F | 57.0 °F | 3.89 in. |
| May | 47.7 °F | 68.4 °F | 4.48 in. |
| June | 57.8 °F | 78.3 °F | 4.6 in. |
| July | 62.7 °F | 82.6 °F | 3.81 in. |
| August | 61.3 °F | 80.9 °F | 3.77 in. |
| September | 53.5 °F | 74.0 °F | 3.55 in. |
| October | 41.9 °F | 61.1 °F | 3.2 in. |
| November | 30.8 °F | 47.0 °F | 2.42 in. |
| December | 20.5 °F | 34.9 °F | 2.14 in. |
| Annual | 39.2 °F | 57.6 °F | 38.03 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| 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 | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |