Official Time :
Standard Time UTC/GMT +3:30 hours
Daylight Saving Time
(applies on 00:00, 21 Mar.- 00:00, 21 Sep. local time)
UTC/GMT +4:30 hours

Business Hours :
Tehran Sat.- Wed. Thr. Fri. & Official Holidays
Banks 08:00-16:00 08:00-12:30 closed
Governmental Offices 07:30-15:30 closed closed

Other Cities Sat.- Wed. Thr. Fri. & Official Holidays
Banks 07:30-13:30 07:30-12:30 closed
Governmental Offices 07:30-14:30 07:30-12:30 closed

Official Calendar
The Persian calendar, Iran's official Calendar is a solar calendar with a starting point that matches that of the Islamic calendar. Its origin can be traced back to the 11th century when a group of astronomers (including the well-known poet Omar Khayyam) created what is known as the Jalaali calendar. However, a number of changes have been made to the calendar since then.
The current calendar has been used in Iran since 1925 and in Afghanistan since 1957. However, Afghanistan used the Islamic calendar in the years 1999-2002(Taliban period).
The names and lengths of the 12 months that comprise the Persian year are:

1 Farvardin 20 Mar.-19 Apr. 31 days
2 Ordibehesht 20 Apr.-20 May. 31 days
3 Khordad 21 May.-20 Jun. 31 days
4 Tir 21 Jun.-21 Jun. 31 days
5 Mordad 22 Jul.-21 Aug. 31 days
6 Shahrivar 22 Aug.-21 Sep. 31 days
7 Mehr 22 Sep.-21 Oct. 30 days
8 Aban 22 Oct.-20 Nov. 30 days
9 Azar 21 Nov.-20 Dec. 30 days
10 Dey 21 Dec.-19 Jan. 30 days
11 Bahman 20 Jan.-18 Feb. 30 days
12 Esfand 19 Feb.-20 Mar.. 29/30 days

The month of Esfand has 29 days in an ordinary year, 30 days in a leap year.
The Persian year starts at vernal equinox. If the astronomical vernal equinox falls before noon (Tehran true time) on a particular day, then that day is the first day of the year. If the astronomical vernal equinox falls after noon, the following day is the first day of the year. As in the Islamic calendar, years are counted since Prophet Mohammed's emigration to Medina in AD 622. At vernal equinox of that year, AP 1 started (AP = Anno Persico/Anno Persarum = Persian year). Note that contrary to the Islamic calendar, the Persian calendar counts solar years. In the year AD 2004 we have therefore witnessed the start of Persian year 1388, but the start of Islamic year 1425. There is a leap year our of each 4 years. (it's more complex and there are some exceptions.)


Official Holidays :
Friday is the official weekend, although Thursday are closed for many businesses.
Iran's official holidays are being extracted from two calendar systems :

1. National Official Calendar (Hijri-Shamsi) which is a Solar Calendar (1 year = 365 days) and is easily comparable to Gregorian (international) calendar.
2. Islamic Calendar (Hijri-Qamari) which is a Lunar Calendar (1 year=355 days) which causes the religious holidays move along the solar year. Hence, as a rule of thumb, national Iranian holidays are fixed on either Iranian National Holiday or International calendar, but the religious holidays must be checked with the official calendars each year.
The following table shows the official holidays for Iranian year 1391 which coincides 21 Mar. 2012-19 Mar. 2013.

International Clndr.Week DayIranian Clndr.
20 Mar. 12Tue. 01.01.1391Norooz
21 Mar. 12Wed..02.01.1391Norooz
22 Mar. 12Thu. 03.01.1391Norooz
23 Mar. 12Fri.04.01.1391Norooz
31 Mar. 12Sat. 12.01.1391IslamicRepublic Day
01 Apr. 12Sun.13.01.1391Day of Nature (Sizde-be-dar)
25 Apr. 12Wed. 06.02.1391Martyrdom ofHazrat-i-Zahra
03 Jun. 12Mon.14.03.1391Commemoration of ImamKhomeini
04 Jun. 12Sun. 15.03.1391Commemoration of 15 Khordad
18 Jun. 12Mon.29.03.1391Mab'as
05 Jul. 12Thu. 15.04.1391Imam Mahdi's Birthday
19 Aug. 12Sun.29.05.1391Eid e Fitr
20 Aug. 12Mon. 30.05.1391Eid e Fitr
12 Sep. 12Wed.22.06.1391Martyrdom of Imam Sadiq
03 Nov. 12Sat. 13.08.1391Eid e Qadir
24 Nov. 12Sat.24.09.1391Tasooa
25 Nov. 12Sun. 25.09.1391Ashoora
03 Dec. 12Thu.14.10.1391Arba'in
12 Jan. 13Sat.29.10.1391Martyrdom of Imam Reza
29 Jan. 13Tue.10.11.1391Birthday of the prophet
10 Feb.13Sun..22.11.1391Anniversary ofthe IslamicRevolution
19 Mar. 13Tue.29.12.1391 Oil Nationalization Day

* The MFA usually does not process applications from 15 Mar.- 1 Apr. for Norooz holidays.
* 28 Aug. - 01 Sep. 2012 is announced as a holiday in Tehran for NAM heads of states summit. The MFA will not be working during this period.