Herscher, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 40.8 °F (low) to 60.9 °F (high). Annual precipitation averages 38.5 Inches. Herscher 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 | 16.2 °F | 32.1 °F | 2.13 in. |
| February | 19.5 °F | 36.7 °F | 1.86 in. |
| March | 28.9 °F | 48.7 °F | 2.43 in. |
| April | 39.2 °F | 61.6 °F | 3.69 in. |
| May | 50.7 °F | 72.6 °F | 4.53 in. |
| June | 60.5 °F | 81.7 °F | 4.63 in. |
| July | 63.9 °F | 84.5 °F | 4.36 in. |
| August | 61.7 °F | 82.9 °F | 3.77 in. |
| September | 53.4 °F | 77.8 °F | 3.19 in. |
| October | 42.1 °F | 64.8 °F | 3.23 in. |
| November | 31.6 °F | 50.1 °F | 2.6 in. |
| December | 21.9 °F | 37.4 °F | 2.1 in. |
| Annual | 40.8 °F | 60.9 °F | 38.52 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 | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |