Acclimatization generally refers to the ability of living things to adjust to changes in climate.
Acclimatization usually occurs in a short time, within the organism's lifetime. Many plants, such as maple trees, irises, and tomatoes, can survive freezing temperatures if the temperature gradually drops lower and lower each night over a period of days or weeks. The same drop might kill them if it occurred suddenly. This process is called hardening. Scientists believe several events cause hardening.