There are 824 GHCN HCN stations which have been continuously active since at least 1920.
Forty percent of those stations set their all-time record maximum temperature during the 1930s. Twenty-one percent set their all-time record maximum temperature in the year 1936 alone.
By contrast, only one percent of those stations set their all-time record maximum temperature in the current decade. Eighty-nine percent of those stations set their all-time record with CO2 below 350 ppm.
NOAA says that 2012 was the hottest year ever in the United States. Only three stations (0.3%) set their all time record maximum during NOAA’s hottest year ever, compared to one hundred seventy two stations (21%) in 1936.
The table above shows stations which set all-time record maximums in 2012.
There were eight times as many all-time record maximums set in 1901 as there were during the hottest year ever 2012.