Frost dates in Iron County, Michigan
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The average last spring frost in Iron County falls May 24 to Jun 6 and the average first fall frost Sep 9 to Sep 25, depending on the ZIP code (50% odds, 32°F, NOAA 1991–2020 normals). USDA hardiness zone 4a to 4b. Places: Alpha, Caspian, Crystal Falls, Gaastra, Iron River. Pick a ZIP for 10% and 90% odds, soil temperature and the 7-day freeze forecast.
| ZIP | Place | Last spring frost | First fall frost | Zone |
|---|---|---|---|---|
| 49902 | Alpha | May 24 | Sep 25 | 4b |
| 49903 | Jun 6 | Sep 9 | 4a | |
| 49915 | Caspian | Jun 4 | Sep 10 | 4a |
| 49920 | Crystal Falls | Jun 6 | Sep 9 | 4a |
| 49927 | Gaastra | Jun 4 | Sep 10 | 4a |
| 49935 | Iron River | Jun 4 | Sep 10 | 4a |
Nearby counties
Dickinson County Baraga County Marquette County Ontonagon County Menominee County Houghton County
All Michigan counties · Download Michigan frost dates (CSV)
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