Notable Trend in Mean Winter Minimum Temperatures

There are some interesting diurnal and seasonal differences within the long term annual mean. A closer look at minimum temperatures during the winter season (defined as the months of December, January, and February) in Ironwood, located in the far western end of Michigan’s Upper Peninsula (graph on left) suggests about a 5ºF increase over the last two decades, which is a “very notable trend” according to Jeff Andresen, Michigan State Climatologist and co-director of the Pileus Project.