Ardabil province is located in the northwest of Iran, and the garlic plant in that province is dominant.Agriculture is considered one of the most important economic activities that more than anything else depends on weather conditions. Therefore, the present research studied the effects of temporal changes in temperature and rainfall on garlic yield in Ardabil Province based on panel data of the 1991-2006 time series and cross-sectional data of 13 Counties in this Province that had higher garlic yields by using the GLS technique. Results showed that for each County the physical variables (the used inputs) in the model (except for the applied pesticides) had significant positive effects on yield. In addition to the physical variables, the rainfall and temperature variables had positive and negative effects on garlic yield, respectively. The contribution of rainfall and temperature to garlic yield were -7.11 and -1.31 percent, respectively. Based on the various Scenarios studied in the research, garlic yield changes in the Counties exhibited greater positive responses to changes in rainfall. By analyzing trend at the station and provincial level, precipitation will decrease and precipitation will increase. Also, by analyzing rainfall, the intensity of rainfall changes with time. This result is true for the lowest and the highest temperatures.
