The Northeast region will potentially experience a decrease in the number of very cold days (below 10°F). The northern Northeast region is modeled to experience the greatest decreases with changes of 21 days or more. The smallest decreases are modeled to occur in coastal and southern areas where the number of occurrences in the present-day climate is small. These simulated decreases in cold days are in line with the recent observed changes in the Northeast region. The fluctuations in winter temperatures may cause mid-winter hardening or late winter premature leaf out, particularly affecting cold-adapted, high-elevation trees and other perennials.