Snow Day Predictor for Chicago, IL

Chicago is a major metro of about 2,664,452 people that sits across the northern mid-latitudes, near 41.9°N in Illinois. A winter here typically brings about 20 to 40 inches a winter. Clipper systems and the occasional ice storm drive most closures. Because the town falls in the Lower Midwest / Plains climate region, our model's closure threshold for Chicago is held to a moderately high bar, reflecting districts that handle snow as a matter of course.

The percentage at the top of this page isn't a static guess — it's rebuilt each night from Chicago's own Open-Meteo forecast. The model reads seven signals from the overnight-into-morning window: total snowfall, whether any of it is timed for the 2–6 a.m. commute, freezing rain or sleet, the coldest air temperature, the wind chill, the peak wind, and how much snow is already on the ground. A solid 3–5" storm, an ice event, or a sub-zero wind chill will typically do it. Two-hour delays are popular here to let plows and the sun do their work.

Because a 2-hour delay clears a lower bar than an outright cancellation, you'll often see delay odds for Chicago even when the closure odds stay modest — that gap is the model flagging a borderline morning. The estimate shifts as the forecast firms up overnight, so it's worth re-checking Chicago's odds the evening before school. Treat it as a well-informed second opinion for planning, never as an official Illinois closing announcement.