How is the weather in Iran
In December and January, Iran has three different kinds of weather. It means that along the Caspian coast, the weather is fair and relatively cold, and at the same time in center parts of the country you experience a winter cold and in southern parts you can enjoy a pleasant and mild weather.
Generally the best time to visit Iran is during the spring and autumn. There are ideal temperatures across most of Iran from March until May and then again from late September to early November. Meanwhile, winter is best avoided because temperatures can become very cold.