| 2023 Hardiness Zone: | Zone 6a: -10°F to -5°F |
| 2012 Hardiness Zone: | Zone 6a: -10°F to -5°F |
| 1990 Hardiness Zone: | Zone 6a: -10F to -5F |
| 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: | 56b - Elkhart Till Plains |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 49002 - Portage, MI | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 16 | 19 | 27 | 37 | 48 | 57 | 61 | 60 | 52 | 41 | 32 | 22 | 39 |
| Avg Max Temp (°F) | 31 | 35 | 47 | 59 | 71 | 80 | 84 | 82 | 74 | 62 | 48 | 36 | 59 |
| Avg Precip (In.) | 2.15 | 1.71 | 2.5 | 3.49 | 3.56 | 3.74 | 3.71 | 3.81 | 4 | 2.97 | 3.04 | 2.7 | 37.37 |