The annual freeze-free season is expected to increase by 20 to 30 days in the Southeast by 2055. The freeze-free season lengthens by more than a month by the late 21st century in climate simulations based on a high emissions scenario.

The freeze-free season is defined as the period of time between the last spring frost (daily minimum temperature below 32 degrees F) and the first fall frost. The length of the annual freeze-free season has been increasing since the 1980s, and all climate models agree that it will continue to increase in the future across the Southeast. The largest increases of 25-30 days are mainly expected in Louisiana, Tennessee, Kentucky, Virginia, and North Carolina. The smallest changes are expected in southern Florida, which is not surprising because freezing events are already rare in this part of the Southeast.