Chicago, Illinois – A sharp temperature drop during the week leading into St. Patrick’s Day could turn part of Illinois’ next rain system into accumulating snow, especially north of Interstate 80, as colder air settles across the Midwest March 11-17.
According to the National Weather Service Climate Prediction Center, Illinois falls within a 40-50% probability of above-normal precipitation during the 8-14 day period, while much of the state also trends near to below normal on temperatures. That colder signal stretches from Minnesota and Wisconsin into northern Missouri and central Illinois, increasing the odds that late-season systems produce wet snow instead of cold rain.
Statewide, the wetter pattern favors repeated systems tracking from the Plains into the Ohio Valley. In Chicago, Rockford and Peoria, surface temperatures hovering in the 30s and low 40s during overnight hours could support slushy accumulation on grassy surfaces if heavier bands develop. Farther south toward Springfield and Carbondale, rain is more likely, but brief mix-ins cannot be ruled out during early morning hours.
The broader eastern U.S. faces a similar active stretch, with above-normal precipitation probabilities extending from the Midwest into the Mid-Atlantic and Northeast. Meanwhile, California, Nevada, Arizona and New Mexico trend drier than normal, highlighting a sharp west-to-east contrast in the national pattern.
Drivers across northern Illinois should monitor pavement temperatures during early morning commutes, particularly on bridges and overpasses. Even minor accumulation can create slick spots if bursts of moderate precipitation align with subfreezing air. Additional updates are expected as the March 11-17 window approaches and confidence in storm timing increases.
