Chicago averages roughly 950 mm (about 38 inches) of rain a year, spread fairly evenly across the seasons but concentrated in strong spring and summer thunderstorm activity. Sitting at the southern tip of Lake Michigan, the city’s weather is heavily shaped by lake effects, which can intensify or redirect storm systems in ways that are hard to predict from a general forecast alone. Severe thunderstorms capable of producing damaging wind, hail, and occasional tornadoes are a real spring and summer risk across the wider Chicago metro area, often developing quickly along squall lines that sweep in from the Plains. Because these systems can go from a distant cluster to a fast-moving line in under an hour, radar tracking gives a much clearer, more immediate picture than a standard forecast update. The region is covered by the National Weather Service’s Doppler radar network based southwest of the city.
Learn more: How Does Rain Radar Work? · Open the full Rain Map