Which parts of Iran have four distinct seasons?

In Iran, the northern and western regions are characterized by four distinct seasons. Additionally, the city of Tehran, located in the central part of the country, also experiences four distinct seasons despite its hot, arid climate.12

In contrast, as one moves toward the south and east of the country, the transitional seasons of spring and autumn become increasingly brief, eventually merging into a climate defined primarily by mild winters and hot summers.1