More global warming.
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Temperatures in Chicago hit an 18-year low overnight, when the mercury dipped to one degree below zero.
It was the first time since 1995 that the temperature was below zero in Chicago, and that’s just the start of frigid conditions.
Though temperatures will get into the low 20s on Tuesday, they could drop below zero again Wednesday night. Before that, Chicago likely will get more snow.
A winter weather advisory has been issued for the Chicago area from midnight Tuesday night through 10 a.m. Wednesday morning.