| 2023 Hardiness Zone: | Zone 6a: -10°F to -5°F Zone 5a: -20°F to -15°F Zone 5b: -15°F to -10°F |
| 2012 Hardiness Zone: | Zone 5a: -20°F to -15°F Zone 4b: -25°F to -20°F Zone 5b: -15°F to -10°F |
| 1990 Hardiness Zone: | Zone 4b: -25F to -20F |
| Average First Frost Date: | Oct. 1 - Oct. 10 |
| Average Last Frost Date: | May 21 - May 31 |
| Koppen-Geiger Climate Zone: | Dfb - Humid Continental Mild Summer, Wet All Year |
| Ecoregion: | 50af - Cadillac Hummocky Moraines |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 49638 - Harrietta, MI | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 9 | 10 | 18 | 30 | 40 | 50 | 54 | 52 | 45 | 35 | 26 | 16 | 32 |
| Avg Max Temp (°F) | 26 | 30 | 39 | 53 | 67 | 75 | 80 | 77 | 69 | 56 | 42 | 31 | 54 |
| Avg Precip (In.) | 2.04 | 1.44 | 2.11 | 2.71 | 2.9 | 3.18 | 3.05 | 3.77 | 3.95 | 3.26 | 2.88 | 2.21 | 33.49 |