Climate and weather conditions are among the most important factors in controlling our daily and even long-term activities. Since the emergence of human beings, the weather has been effective in our lives. Changes in precipitation and temperature, solar radiation and other climatic parameters, have had so much impact on people’s lives that as far back as the first periods of human lives, we have been witnessing the climate change, and these factors have determined the way of our lives. Since the old days, the scientists of criminology, sociology and psychology have considered the influence of nature and different circumstances on the crime and its rate. Hippocrates and Montesquieu were the oldest ones that studied about the impact of climate on effects and aggressive behavior. The main objectives of this research are as follows: Understanding the climatic regions of Kurdistan Province, and assessing the relationship between the climatic regions of the provinces and the aggression rate. From a psychological perspective, aggression is a behavior whose aim is to harm others or oneself with a conscious intent. The main idea of this study is to consider the theory that whether there is any connection between natural factors, especially the weather, and the mood, temperament and the aggression rate of people. For this purpose, and for climatic zoning of Kurdistan, we have used the surface data of all synoptic stations in Kurdistan as well as the stations around the province from their establishment until 2005 (25 stations). Using these data, 2068 cells (with approximate dimensions of 7/3 * 7/3 km²) in Kurdistan were appraised every day according to the Kriging interpolation. By applying the cluster analysis to these data, two main climatic zones were identified in Kurdistan. The hot-humid region was including the cities Bane, Marivan, Sarouabad, Sanandaj and Kamyaran, and the cold-dry region, was including the cities Saghez, Diwandareh, Bijar, Ghorveh and Dehgolan. Then in each of these regions, in the number of the samples which were obtained through Cochran formula (768 samples), the Buss and Perry questionnaires were distributed and collected. The new version of the Aggression Questionnaire, whose previous versions was hostile questionnaire, was revised by Buss and Perry (This is a self-report questionnaire that contains 29 words and four subscales).The prototype questionnaire has 52 questions, but a lot of weak questions of the questionnaire have been excluded using the factor analysis method, and it has turned into a questionnaire with 29 questions. Finally, the results of the questionnaires were analyzed through SPSS, using the t test for the independent groups. The results of this study indicate that the physical and verbal aggression rate and the level of anger and hostility among the residents of the cold regions of Kurdistan are higher than the residents of warmer regions. The results also showed that the level of aggression among the men is higher than women. The aggression among the men mostly appears in a physical form, while women make it in its verbal form. Also, in the hot-humid areas, the level of anger and hostility among the women is more than men. According to the data analysis, we can say that the results of this study are consistent with the findings of some researchers, though in some cases the results are not consistent with other researches. The assessment of the geographical environment has not concerned the scientists alone, and philosophers like Ibn Sina, Sociologists like Ibn Khaldun, and writers and thinkers such as Al-Jahiz have looked at geographical factors from other perspectives, and have examined its relationship with ethics and human behaviors. In conclusion, we can say that the results of this study are non-aligned with the results of the studies that have examined the effect of weather conditions on the temperament or real aggression. But the results of this study are consistent with the researches that have investigated the potential of aggression. Therefore, we can say that in a short period of time, warm weather conditions can predispose one to aggression, but to live in the warm climates, may raise people`s patience at the end, and make them able to control themselves at the occurrence of aggression. The results of this study indicate that in Kurdistan province, the extent of potential aggression is higher among the residents of the cold regions (Saghez, Diwandareh, Bijar, Ghorveh and Dehgolan) than the inhabitants of the tropic ones (Bane, Marivan, Sarouabad, Sanandaj, and Kamyaran). To justify these findings, we can say that freezing creates a sense of insecurity in people because we experimentally see that the residents of a cold region need to work constantly in order to keep their bodies warm. They need to have a secure plan for the winter, so that they can make enough food, fuel and clothing. This coherent planning makes them more active in comparison with the residents of the tropical regions. An unfavorable and difficult living environment emboldens people. The people who belong to these areas are pragmatic, and their approach to the environment is competitive or aggressive. In contrast, the people who live in the relatively warmer climate have usually less activity. The property of this kind of temperament is laziness and inertia. Working in hot places is unpleasant because it makes people sweat, and it makes them tired soon. Another finding of this study is that in the whole province, in both cold and warm climates, the aggression among men is more than women, and this difference is greater in cold areas. The men spend most of their time outside the houses, and because of this, the effect of climate is more on them, but women are living most of their time at home, and they can take advantage of the air conditioning equipment. Thus, they have a more relaxed and flexible temperament.