Since the winter of 1995-1996 there have not been any extreme cold weather events in eastern Kentucky where temperatures have fallen well below zero. This unusually long stretch of winters without extreme cold is unprecedented in the past 100 years.
The coldest temperatures so far this winter occurred the weekend of February 11 to February 12, when minimum temperatures for most areas in eastern Kentucky fell to between 10 and 15 degrees. Even with the recent cold snap, this winter is on pace to have some of the warmest winter time minimum temperatures on record.
For example, at Jackson, where records date back to 1981, the coldest temperature observed so far this winter has been 12 degrees. Prior to this year the warmest observed winter time minimum temperature at Jackson was 11 degrees in the winter of 1997-1998. The following graph shows the lowest temperature observed at Jackson for each winter season dating back to January 1981. As can be seen there has been an absence of extreme cold weather events since the mid 1990s.
At London the lowest observed temperature so far this winter has been 13 degrees. Prior to this year, the warmest winter time minimum temperature observed at London was 10 degrees in the winter of 2001-2002. Records at London date back to the winter of 1954-55. The following graph shows the lowest temperature observed at London for each winter season dating back to 1954-55. As is the case at Jackson, extreme cold events have not occurred at London since the middle 1990s.
There are a few locations in eastern Kentucky where temperature records date back over 100 years. Farmers in Rowan County is one such location. Records at Farmers date back to the winter of 1904-1905. The following graph shows the lowest temperature observed at Farmers for each winter dating back to 1904-1905. Once again the unusual absence of extreme cold weather events since the mid 1990s is very apparent. The lowest temperature observed so far this winter at Farmers has been 11 degrees. The only other winter with the coldest observed temperature being this warm was the winter of 1936-1937 when the lowest recorded temperature was also 11 degrees.
Temperature records at Williamsburg, Kentucky date all the way back to 1896-1897. It should be noted that the observing station at Williamsburg was moved to a new location in 2004. The following graph shows the lowest temperature observed at Williamsburg for each winter dating back to 1896-1897. As is the case at Jackson, London, and Farmers there has been an unusually long stretch of winters without extreme cold dating back to the middle 1990s. At Williamsburg the temperature has not been below zero since the winter of 1995-1996. The coldest temperature so far this winter at Williamsburg has been 16 degrees. The only other winter when the observed lowest temperature was warmer than this was the winter of 1920-1921 when the observed lowest temperature was 17 degrees.
The final three graphs show 11 year running averages for winter time minimum temperatures observed at London, Farmers and Williamsburg. In these graphs for any given winter, the temperature plotted is the average coldest minimum temperature observed during the 11 year period centered on that winter. For example the -7.7 plotted for London for the winter of 1959-60 indicates that for the 11 winters from 1954-55 through 1964-66 the average coldest temperature observed each winter was -7.7.
These final three graphs may be the most revealing of all, as they average out the year to year variability in winter time minimum temperatures, and show how average winter time minimum temperatures have been rising across eastern Kentucky for most of the past 20 years. It will be interesting to monitor winter time temperatures in the coming years to see if the trend towards fewer and fewer extreme cold events continues.