Decided to quantify the changes in early spring temperatures by comparing the average March high temperatures in the late 19th century to the most recent 13 years (2010-2022). I used average high temperatures to somewhat minimize the impacts of urban heat island effect. What we can see are absolutely prodigious changes. Large cities in the lower Great Lakes (Cleveland, Detroit, Chicago, Buffalo) experienced 19th century early spring temperatures which were generally cooler than Green Bay, W