| 2023 Hardiness Zone: | Zone 5a: -20°F to -15°F Zone 5b: -15°F to -10°F Zone 4b: -25°F to -20°F Zone 4a: -30°F to -25°F |
| 2012 Hardiness Zone: | Zone 4b: -25°F to -20°F Zone 4a: -30°F to -25°F |
| 1990 Hardiness Zone: | Zone 3b: -35F to -30F |
| Average First Frost Date: | Sep. 21 - Sep. 30 |
| Average Last Frost Date: | May 21 - May 31 |
| Koppen-Geiger Climate Zone: | Dfb - Humid Continental Mild Summer, Wet All Year |
| Ecoregion: | 50d - Ontonagon Lobe Moraines and Gogebic Iron Range |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 49938 - Ironwood, MI | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 0 | 4 | 14 | 28 | 40 | 50 | 55 | 53 | 44 | 34 | 21 | 7 | 29 |
| Avg Max Temp (°F) | 19 | 25 | 36 | 50 | 64 | 73 | 77 | 75 | 65 | 53 | 36 | 24 | 50 |
| Avg Precip (In.) | 2.05 | 1.21 | 2.07 | 2.12 | 3 | 4.12 | 3.98 | 3.73 | 3.79 | 3.38 | 3.07 | 2.05 | 34.58 |