Knowing wind energy and its features can help programmers in using this clean, free and renewable energy. Iran is located in the west wind region, and the common wind direction is from north-west to south-west in Iran. But in some regions of Iran, due to special regional conditions as well as the synoptic factors of atmosphere, the wind direction is different from the common wind direction in Iran. The wind speed is also higher than the average speed of west winds.
Based on the statistics from wind speed and direction in 120 synoptic stations, Iran is divided into ten big wind classes each of which regarding wind speed and direction has its own special features during different times of year. The most spread class is Sistan class that includes vast section of Sistan and Bluchestan, Kerman, South Khorasan, Razavi Khorasan, Yazd and Isfahan provinces.