This is a graphic from NOAA showing how much of the US is experiencing a summer heat wave and how that has changed over the years. I haven’t figured out how they were able to produce that graph yet.
Instead, here here is a graph based on readings from all the US land stations. Produced simply by counting the number of stations that reached 95F any time that year. Clearly, fewer and fewer stations are experiencing 95F.
Here is the same graph but this time we drop the temperature and now we are counting the number of stations that reached 90F any time that year. Very similar results. Still a downward trend, but less severe.
Slightly different approach. Lets count the number of days that stations reported above 95F temperatures. Now we are seeing the size of the heat waves whereas before we were seeing places that experienced heat waves. Surprisingly we see a similar downward trend. Not at all what NOAA is showing us.
Finally, here is the