I am a co-author of the U. S. Global Change Research Project’s latest national climate assessment chapter on the Southeast. Some of the things that we look at are indicators of how climate is changing based on variables like temperature, precipitation, and related quantities like growing season length, heat waves, and other factors. If you are interested in exploring how some of these things are changing over time, here is a good catalog from USGCRP that provide insights into how the climate has changed over time.