If the leaf is wet and water is not freezing on it, the leaf can theoretically cool to the wet bulb temperature. Even though wind chill does not apply to plants, wind can remove heat from a grove rapidly. Hence, the length of time a grove will be at low temperatures can be longer on a windy night than on a calm one. Thus, more damage can potentially occur during a windy freeze. Conclusion Humidity plays an important role in freezes, particularly if one is using water for cold protection.
Water is a two-edged sword that can either help or hurt when used during a freeze.
An understanding of humidity concepts and water principles can help a person use irrigation for cold protection successfully. This document is Fact Sheet HS-76, a series of the Horticultural Sciences Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Lawrence R. Parsons, Professor, Horticultural Sciences, Citrus Research and Education Center, Lake Alfred, FL, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611. For information on obtaining other extension publications, contact your county Cooperative Extension Service office.