> In nearby Boulder, Co., weather stations recorded one-hour temperature drops of 31 to 39 degrees.
Of course, the one-hour temperature drops were only the beginning. The temperature in Denver continued to free fall to a Thursday morning low of minus-24, just short of the lowest-ever December reading of minus-25 on Dec. 22, 1990. Overall, the temperature in Denver dropped 71 degrees in 17 hours, which appears to be the third-largest two-day temperature change on record.