Illinois State Climatologist Jim Angel has crunched the numbers, and thinks (contra my own fears) that we might not get melted into little puddles of goo this summer after all:
Historically, a warm March has been followed by a colder-than-normal April on average (first map). That’s true not just in Illinois but across the U.S. On the other hand, precipitation for those same April periods was a mixed bag in Illinois (second map). Most of the state was near-normal while west-central Illinois was slightly wetter-than-normal.
I considered the entire May-August period in one set of maps. One popular question I get is “Does this warm weather now mean that we will get a hot summer?” At least historically, the growing season following a warm March does not show a pattern of above-normal temperatures. On average, they have been remarkably mild in temperature.
I still worry that the really warm lake temperatures and the lack of snow cover during the winter, followed by an unprecedented 8 days of 27°C weather this month (not to mention the hottest March in recorded history), can't help but yield a brutal summer.
Angel has the data, though. I tend to trust data. I should be reassured...but I'm also from Chicago.