Jerseyville, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 44.8 °F (low) to 64.4 °F (high). Annual precipitation averages 41.7 Inches. Jerseyville is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 21.0 °F | 37.5 °F | 2.46 in. |
| February | 24.4 °F | 42.9 °F | 2.26 in. |
| March | 33.4 °F | 53.5 °F | 3.19 in. |
| April | 44.0 °F | 65.2 °F | 4.61 in. |
| May | 55.1 °F | 74.8 °F | 5.14 in. |
| June | 64.4 °F | 83.4 °F | 4.17 in. |
| July | 67.5 °F | 86.7 °F | 3.61 in. |
| August | 65.4 °F | 85.7 °F | 3.7 in. |
| September | 56.9 °F | 79.3 °F | 3.38 in. |
| October | 45.4 °F | 67.7 °F | 3.21 in. |
| November | 34.6 °F | 53.6 °F | 3.45 in. |
| December | 25.8 °F | 42.2 °F | 2.55 in. |
| Annual | 44.8 °F | 64.4 °F | 41.73 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |