What plant hardiness zone is Isle Royale Natl Park

Isle Royale Natl Park is located at Keweenaw County, Michigan (MI), USA.

Plant hardiness zone (winter frost zone or gardening zone) for Isle Royale Natl Park is 4b by the USDA scale.

Coldest zone's winter temperature is −25 … -20 °F.

Plants of 4b USDA hardiness zone suitable for outdoor gardening and growing in this winter frost zone 4b USDA.

Isle Royale National Park @ wikipedia.