The number of very hot days is projected to rise at a greater rate than the average temperature. Average temperatures in the [Southeast] region are projected to rise by about 4.5°F by the 2080s, while a higher emissions scenario yields about 9°F of average warming (with about a 10.5°F increase in summer, and a much higher heat index).
It is not easy to grasp those numbers, because we assume that global averages and daily or hourly temperature changes are equivalent, and they aren’t. Since 1970 our average temperature in this region has risen 2 degrees, which is roughly the same change for the Southeast as occurred between now and the last time glaciers extended below the Great Lakes. So, just to begin with, 2 degrees is huge. It is the difference between southern Mississippi and Nashville, Tennessee. Trying to grasp what “about 4.5°F by the 2080s” will mean, never mind 9°F… fuggeddaboudit.