There is a saying in Colorado that states, "If you don't like the weather in Colorado, wait five minutes."
If you like cold weather in January, it usually requires waiting a few days for a warm spell to end, but rapid changes in winter temperatures are not that uncommon in Southeast Colorado. Over the last 100 years, there have been eight occasions when the daily maximum temperature in Pueblo has changed by more than 60 degrees within a one week period. All of these extreme temperature changes have occurred during the Winter months of December through February. The most extreme example occurred in 1989, when the temperature went from a high of 75 degrees on January 31, to a high temperature of minus 1 degree on February 4th. In each of the eight cases where temperatures changed by 60 degrees or more, the extreme low temperatures followed the unusually warm weather.
This past week did not come close to matching the extreme swing of 1989, but after a high temperature of 75 degrees in Pueblo on January 21, the high today, January 26, of 17 degrees was still quite a dramatic change. The cold air was the result of a strong surface high pressure system over the Upper Midwest, that ushered in a shallow layer of cold Canadian air from the northeast.