Chicago is currently experiencing a noticeable shift in weather patterns, marked by lake-effect chills that are impacting the region. As reported by NBC Chicago, this phenomenon occurs when cold air masses move across the relatively warmer waters of Lake Michigan. This interaction results in the air being warmed and picking up moisture, which then leads to cloud formation and, under the right conditions, precipitation in the form of snow or enhanced cool breezes. The lake-effect is particularly pronounced during the transitional seasons, such as spring and early winter, when the temperature difference between the lake and the air is greatest.