Vienna, Illinois has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 47.2 °F (low) to 67.2 °F (high). Annual precipitation averages 50 Inches. Vienna is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 25.6 °F | 42.3 °F | 3.8 in. |
| February | 28.6 °F | 46.6 °F | 3.44 in. |
| March | 36.7 °F | 56.3 °F | 4.66 in. |
| April | 46.5 °F | 68.1 °F | 5.37 in. |
| May | 56.8 °F | 76.8 °F | 5.34 in. |
| June | 65.1 °F | 85.0 °F | 4.59 in. |
| July | 68.8 °F | 88.1 °F | 4.04 in. |
| August | 66.5 °F | 87.3 °F | 3.03 in. |
| September | 58.7 °F | 81.6 °F | 3.42 in. |
| October | 47.2 °F | 70.7 °F | 3.77 in. |
| November | 36.8 °F | 57.0 °F | 4.37 in. |
| December | 29.4 °F | 46.0 °F | 4.19 in. |
| Annual | 47.2 °F | 67.2 °F | 50.02 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |