 The county has a humid continental climate (Köppen "Dfb"), slightly moderated by its proximity to Lake Superior.Winters are long, snowy, and very cold, normally seeing maximum temperatures remaining below on 106 days.Due to global warming, in January 2019 Tracy Twine, professor at the University of Minnesota’s Department of Soil, Water and Climate, said "we just don’t expect temperatures to be below 10 degrees Fahrenheit in Duluth anymore.