Was thinking about beavis' comment about summer wx being more reliable in JJA in contrast to winter wx not being as reliable around Chicago. I think there's some merit to that. Think about it. Summer months and months that are adjacent to summer have a tighter range of temperature anomalies than what can occur in winter. It simply cannot get as far above or below average in summer. Around Chicago, a few degrees below average in summer still feels reasonably summer-like, but a few degrees above average in winter means you are probably going to start melting any snowcover that you have, and it has been a struggle to build up any decent snowcover this winter especially north/west of the city.
Chicago is better than a lot of other places for wintry wx, but it's still kind of living on the margins with not a whole lot of room for error.