As the polar vortex leaves its mark across most of the U.S. with temperatures expected to dip to new record lows, Chicago will be one of the coldest areas, with temperatures expected to dip to new record lows. The forecast predicts temperatures in the Windy City will hit minus 23 degrees F (minus 30.5 degrees C), reports The Chicago Tribune.

To put that into perspective, Chicago will be colder than Antarctica and Siberia.

Hundreds of flights have already been cancelled, and the city and several nonprofit groups are scrambling to open additional shelters for the homeless. Even the Brookfield Zoo is closing for two days to ensure the safety of the animals and employees, reports the Associated Press. Core staff will be on hand to take care of the animals. It's only the fourth time in the zoo's 85-year history that the attraction has been closed.

Editor's note: This story has been updated since it was originally published in March 2013.

Chicago will be colder than Antarctica this week
Chicago prepares for a record-breaking winter storm — all thanks to the polar vortex — and the weather comparisons keep on coming.