Let's say summer is 100 days, and "normally" there are 10 days of 90-degree highs (the hot days) and 90 days of 70-degree highs. That's an average high of 72 de

Let's say summer is 100 days, and "normally" there are 10 days of 90-degree highs (the hot days) and 90 days of 70-degree highs. That's an average high of 72 degrees. Now, if you have a summer with one additional hot day, the average high is 72.2 degrees, which is about the 0.23 degree average increase observed. Obviously these numbers are made up, but could you really just casually notice only one more hot day than normal? It seems like you'd need to be keeping count to have any sort of confidence that this summer was hotter than normal.