http://www.ncdc.noaa.gov/oa/climate/research/cag3/na.html
From 1927 to 1936, summer temperatures in the US warmed at a rate of almost 40 degrees per century, even after USHCN chopped a couple of degrees off the 1930s!
Climate is linear, so we can expect summers over the boiling point in several generations.
If there were no satellites to record it, it didn’t happen.
before 1950 also, impossible to have happened.
So the average high temperatures of 110 in Oklahoma are pretty close to the mark!