| 2023 Hardiness Zone: | Zone 6a: -10°F to -5°F 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: | May 11 - May 20 |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers |
| Ecoregion: | 53b - Kettle Moraines |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 53024 - Grafton, WI | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 12 | 16 | 26 | 36 | 46 | 55 | 62 | 61 | 53 | 42 | 30 | 18 | 38 |
| Avg Max Temp (°F) | 27 | 31 | 41 | 53 | 65 | 75 | 80 | 78 | 71 | 59 | 44 | 32 | 55 |
| Avg Precip (In.) | 1.48 | 1.2 | 1.99 | 3.24 | 2.96 | 3.63 | 3.8 | 4.15 | 3.45 | 2.39 | 2.36 | 1.85 | 32.48 |