The CA Department of Motor Vehicles states that California does recognize a valid driver license that is issued by a foreign jurisdiction (country, state, territory) of which the license holder is a resident. California however does not recognize an International Driving Permit (IDP) as a valid driver license.

The IDP is only a translation of information contained on a person's foreign driver license and is not required to operate a motor vehicle in California. Citations issued to a person in California who has an IDP, but does not have a California driver license will be placed on the Department of Motor Vehicle database.

The United States and over 100 other countries are party to the International Convention on Road Traffic. The agreement requires the US and its states to allow a foreign driver admitted to the US to drive a private motor vehicle for one year on certain conditions. Iran is also one of the countries that is party to this Convention so you should be able to drive in California with your Iranian driving license while a tourist here visiting however you should check with CA DMV to find out for certain and see what all you should carry with you when driving a car.