| 2023 Hardiness Zone: | Zone 5a: -20°F to -15°F Zone 4b: -25°F to -20°F |
| 2012 Hardiness Zone: | Zone 4b: -25°F to -20°F Zone 4a: -30°F to -25°F |
| 1990 Hardiness Zone: | Zone 4a: -30F to -25F |
| Average First Frost Date: | Sep. 21 - Sep. 30 |
| Average Last Frost Date: | Jun. 1 - Jun. 10 |
| Koppen-Geiger Climate Zone: | Dfb - Humid Continental Mild Summer, Wet All Year |
| Ecoregion: | 50k - Wisconsin/Michigan Pine Barrens |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 49801 - Iron Mountain, MI | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 0 | 4 | 16 | 29 | 41 | 50 | 55 | 53 | 45 | 34 | 22 | 9 | 30 |
| Avg Max Temp (°F) | 23 | 28 | 38 | 53 | 67 | 76 | 80 | 77 | 68 | 56 | 39 | 27 | 53 |
| Avg Precip (In.) | 1.32 | .88 | 1.77 | 2.24 | 3.11 | 3.46 | 3.55 | 3.8 | 3.7 | 2.64 | 2.05 | 1.44 | 29.94 |