| 2023 Hardiness Zone: | Zone 5b: -15°F to -10°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 |
| Heat Zone Days: | 1 - 7 days Over 86°F |
Annual Climate Data for ZIP Code 61254 - Geneseo, IL | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 13 | 19 | 29 | 40 | 51 | 61 | 65 | 63 | 54 | 43 | 31 | 19 | 41 |
| Avg Max Temp (°F) | 29 | 34 | 47 | 61 | 73 | 82 | 85 | 83 | 76 | 63 | 47 | 33 | 60 |
| Avg Precip (In.) | 1.48 | 1.52 | 2.66 | 3.69 | 4.2 | 4.27 | 3.92 | 4.33 | 3.28 | 2.93 | 2.77 | 2.1 | 37.17 |