Annual Holidays in Iran:

The official weekend holiday in Iran is Friday. Iranian religious holidays are based on lunar system while the Persian calendar is based on Solar system. Religious holidays are subject to change depending upon the official sighting of the moon. Generally in the below-mentioned banking holidays which are mostly religious, all the historical sites and museums are not working.
Note: In Iran we have some public holidays that are only bank holidays and tourists sites are open but during the dates in red, all sites are closed. 

11 Feb Revolution Day
13 Mar Martyrdom of Fatima
19 Mar Oil Nationalization Day
20 Mar Norooz (Persian New Year)
21 Mar Norooz Holiday
22 Mar Norooz Holiday
23 Mar Norooz Holiday
30 Mar Birthday of Imam Ali
14 Apr Prophet’s Ascension
01 May Imam Mahdi’s birthday
4 Jun  Demise of Imam Khomeini
5 Jun Martyrdom of Imam Ali
15 & 16 jun Eid-e-Fetr (End of Ramadan)
09 Jul Martyrdom of Imam Sadeq
22 Aug Eid-e-Ghorban (Feast of Sacrifice)
30 Aug Eid-al-Ghadir
20 Sep Tassoua
21 Sep Ashura
31 Oct Arbaeen
06 Nov The Murder And Matrydom of prophet Mohammad
09 Nov Martyrdom of Imam Reza
26 Nov Birthday of Muhammad and Imam Sadeq