One of Chicago’s four coldest early season days

In 136 years of Chicago weather records, temperatures have failed to climb above 40° only three times this early in the season. That puts the climatological odds of a reading that cold at just 2%. With Thursday’s high predicted to reach just 38°, the sub-40° early season tally since 1871 appears poised to increase to four. Not only would that reading tie the 89-year old record for the coldest October 12 daytime maximum temperature, the reading equals the normal daytime high here on Dec. 6.
The abnormal chill has prompted nighttime freeze watches and warnings across sections of 15 states from Colorado to western Pennsylvania and has reached the Chicago area in an October already running 5° behind the comparable a year ago. September and October are the only two months of 2006 which have registered sub-normal temperatures.
-Tom Skilling