| 2023 Hardiness Zone: | Zone 7a: 0°F to 5°F |
| 2012 Hardiness Zone: | Zone 6b: -5°F to 0°F Zone 7a: 0°F to 5°F |
| 1990 Hardiness Zone: | Zone 6a: -10F to -5F |
| Average First Frost Date: | Oct. 21 - Oct. 31 |
| Average Last Frost Date: | Apr. 11 - Apr. 20 |
| Koppen-Geiger Climate Zone: | Cfa - Humid Subtropical Climate |
| Ecoregion: | 71n - Southern Shawnee Hills |
| Heat Zone Days: | 61 - 90 days Over 86°F |
Annual Climate Data for ZIP Code 62995 - Vienna, IL | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 24 | 28 | 36 | 45 | 55 | 63 | 67 | 65 | 57 | 46 | 37 | 28 | 46 |
| Avg Max Temp (°F) | 42 | 48 | 58 | 69 | 77 | 86 | 89 | 88 | 82 | 71 | 57 | 46 | 68 |
| Avg Precip (In.) | 3.33 | 3.46 | 4.55 | 4.65 | 4.88 | 4.28 | 3.91 | 3.39 | 3.16 | 3.16 | 4.54 | 4.13 | 47.44 |