Contrary to the nonsensical Climate Extremes Index published by NCDC, the US climate is getting much less extreme.
The graph below plots the average percent of stations which recorded temperatures over 100ºF, or below 0ºF per year. The most extreme year was 1936, when 75% of stations recorded 100 degree temperatures, and 66% of stations recorded temperatures below 0ºF.
As you can see, the last twenty years have been the least extreme since the first decade of the last century.
The fraudsters at NCDC count mild weather as being extreme. They rated the winter of 2012 as being the most extreme in history, because the weather was very mild in the US most of the winter. It is straight out of Orwell.