Dear Tom,
How many days in the winter does the temperature here in Chicago drop to zero
degrees or lower?
Jeff Honeycutt, Chicago
Dear Jeff,
It's greatly dependent upon where you are located in the metropolitan area. All the heat
generated in a city eventually escapes into the air, and Chicago promptly removes
snow, which effectively radiates heat away. In addition, Chicago sits adjacent to Lake
Michigan, whose water is a potent winter heat source. Chicago is therefore an "urban
heat island" whose effect, greatest in the core of the city near the lake, diminishes
outward into the suburbs and the rural countryside.
On average, the Loop experiences about six days annually with nighttime low
temperatures at or below zero; inland about four to seven miles, that number increases
to eight or nine days, and at ten miles, to 11-12 days; still farther out, in the rural
countryside, especially to the west, to 15 days.
