| 2023 Hardiness Zone: | Zone 5a: -20°F to -15°F Zone 5b: -15°F to -10°F | |
| 2012 Hardiness Zone: | Zone 5a: -20°F to -15°F | |
| 1990 Hardiness Zone: | Zone 5a: -20F to -15F | |
| Average First Frost Date: | Oct. 1 - Oct. 10 | |
| Average Last Frost Date: | May 1 - May 10 | |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers | |
| Ecoregion: | 52b - Paleozoic Plateau/Coulee Section | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 61074 - Savanna, IL | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 10 | 15 | 27 | 38 | 49 | 59 | 63 | 61 | 52 | 40 | 29 | 17 | 38 |
| Avg Max Temp (°F) | 28 | 34 | 46 | 60 | 72 | 81 | 85 | 83 | 75 | 63 | 47 | 33 | 59 |
| Avg Precip (In.) | 1.33 | 1.36 | 2.44 | 3.51 | 4.09 | 4.57 | 3.65 | 4.48 | 3.36 | 2.65 | 2.65 | 1.89 | 35.99 |