High prices and government plans to increase citrus production have stimulated interest in increased citrus planting in Iran. With favorable soils, availability of water, and the existence of limited planting of citrus in village gardens, commercial planting of citrus is a development of interest for a new irrigation project in southwestern Iran. A severe freeze in 1964 posed questions concerning the suitability of the climate for citrus. Lacking long-term climatological records, analysis was made of daily historic synoptic weather maps from which freezes were forecast in retrospect. Results of this analysis are compared with similar analyses for citrus producing areas near Brownsville, Texas and Yuma, Arizona.