| 2023 Hardiness Zone: | Zone 6a: -10°F to -5°F | |
| 2012 Hardiness Zone: | Zone 5b: -15°F to -10°F | |
| 1990 Hardiness Zone: | Zone 5a: -20F to -15F | |
| Average First Frost Date: | Oct. 11 - Oct. 20 | |
| Average Last Frost Date: | Apr. 21 - Apr. 30 | |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers | |
| Ecoregion: | 54a - Illinois/Indiana Prairies | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | 15 - 30 days Over 86°F |
Annual Climate Data for ZIP Code 61734 - Delavan, IL | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 15 | 20 | 30 | 40 | 51 | 61 | 64 | 62 | 54 | 43 | 32 | 21 | 41 |
| Avg Max Temp (°F) | 32 | 38 | 51 | 64 | 74 | 84 | 87 | 85 | 78 | 67 | 51 | 37 | 62 |
| Avg Precip (In.) | 1.7 | 1.7 | 2.96 | 3.56 | 4.29 | 4 | 4.03 | 3.54 | 3.2 | 2.8 | 3.07 | 2.61 | 37.45 |