Tehran time is GMT plus three and a half hours. Iran has now introduced c (the clocks change by an hour in March and September) so that for a few weeks there may be an extra hours difference with Continental Europe.
Friday is the day of prayer in Iran and all shops, businesses and offices close then. Thursday is half-closing day for many shops and offices. On other days, opening hours can vary quite considerably from one region to another. In general, shops close for an hour or two at lunchtime and stay open until 8 pm, whereas government offices are only open from 8 am to 2 pm.
Mosques, Museums and Historical Sites
There is generally no problem for non-Muslims to visit mosques in Iran, except perhaps during Friday prayer. Shoes can be worn inside the mosques but should be taken off where carpets have been laid down, usually in front of the mehrab. However, in the imamzadeh (mausoleums of the descendants of Imams), it is necessary to take one's shoes off before entering the building. Remember to ask permission to take photographs inside the imamzadeh even if there are no signs expressly forbidding it. In some imamzadeh, such as Abdol Azim's in Ray, women must wear a chador, which can be hired at the entrance.
At Qom and Mashbad, the most important pilgrimage centers in Iran, entrance to the holy shrine is forbidden to non-Muslims (with the exception of certain areas in Mashhad) .
The opening times and days of museums and historical sites is often one of the most frustrating problems for the tourist in Iran. Most museums have fixed opening times, with one closing day a week. Unfortunately, these times can change suddenly
and those tourists with itineraries fixed in advance may have to cancel some visits or replace them.
At the most important sites, such as Persepolis, Pasargadae, or Susa, tickets are sold at the entrance, but some sites, particularly those away from the major towns, are unfenced and do not even have a guardian. Occasionally, it will be necessary to find the guardian and get him to unlock the gate. Should he be absent, you may even have to come back later or the next day. It is therefore recommended to have as flexible an itinerary as possible if you are determined to see a particular place, or to telephone in advance to be sure of getting in. Sites well away from large cities are often impossible or extremely difficult to get to by public transport; for these, it is best to hire a car and a driver if you are not travelling with an organized tour.