Why is it extremely cold in northwestern Illinois where I live? Global warming.

New York Times - U.S. Midwest Freezes, Australia Burns: This Is the Age of Weather Extremes

As for the extremely low temperatures this week in parts of the United States, they stand in sharp contrast to the trend toward warmer winters. They may also be a result of warming, strangely enough.

Emerging research suggests that a warming Arctic is causing changes in the jet stream and pushing polar air down to latitudes that are unaccustomed to them and often unprepared. Hence this week’s atypical chill over large swaths of the Northeast and Midwest.