Introduction: Main regions of citrus plantation are between 40 degrees northern and southern geographical latitudes. A considerable part of these regions are located at Mediterranean sub tropic (WMO, 1997). Citrus plantation has grown into a global industry for the last 70 years. Producing oil and citric acid is another reason for citrus plantation besides fresh fruit production. Temperature is the most important climatic element in citrus plantation. On the one hand, frosts to threaten yield and on the other hand, high Temperatures through extreme transpiration, make the fruit formation difficult. Optimum means daily temperature for citrus growth is from 23 to 30 degrees Celsius and growth is considerably reduced if the temperature is organization, 2004). Another effective process in the occurrence of heat waves at the southern strip is the air subsidence at a synoptically scale. Regarding the above mentioned studies, the most significant climatic restrictions that affect the yield quantity and quality in southern provinces are high temperature and air dryness.