Longview, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 42.5 °F (low) to 62.3 °F (high). Annual precipitation averages 39.7 Inches. Longview 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 | 18.5 °F | 34.2 °F | 2.38 in. |
| February | 21.6 °F | 38.8 °F | 2.04 in. |
| March | 30.8 °F | 50.5 °F | 2.8 in. |
| April | 41.4 °F | 63.7 °F | 4.39 in. |
| May | 52.8 °F | 74.2 °F | 4.42 in. |
| June | 62.1 °F | 82.5 °F | 4.55 in. |
| July | 64.7 °F | 84.8 °F | 4.07 in. |
| August | 62.4 °F | 83.5 °F | 2.74 in. |
| September | 55.1 °F | 78.9 °F | 3.17 in. |
| October | 43.4 °F | 66.2 °F | 3.3 in. |
| November | 32.8 °F | 51.5 °F | 3.33 in. |
| December | 24.2 °F | 39.2 °F | 2.49 in. |
| Annual | 42.5 °F | 62.3 °F | 39.68 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°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 |