| 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. 21 - Oct. 31 |
| Average Last Frost Date: | May 1 - May 10 |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers |
| Ecoregion: | 54e - Chiwaukee Prairie Region |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 60096 - Winthrop Harbor, IL | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 13 | 17 | 27 | 36 | 47 | 56 | 62 | 62 | 54 | 42 | 31 | 19 | 39 |
| Avg Max Temp (°F) | 29 | 33 | 42 | 52 | 65 | 74 | 80 | 79 | 71 | 60 | 46 | 34 | 55 |
| Avg Precip (In.) | 1.63 | 1.34 | 2.25 | 3.76 | 3.37 | 3.67 | 3.67 | 4.21 | 3.46 | 2.49 | 2.65 | 2.07 | 34.58 |