Islamic Calendar

2 Calendars operate in Turkey. The official Turkish calendar is exactly the same as that used almost everywhere else, the Gregorian. Religious festivals however follow the Hijri calendar - a lunar calendar which is offset from the Gregorian by 11 days every year. The practical effect of this is that the positions of the various religious holidays and festivals are not fixed but rather move in relation to the year. This year for example was particularly interesting and presented a conflict of interests. The first day of fasting coincided with new year's eve, tricky one really.

Practicalities

The government has to balance the secular nature of the Turkish republic with the wishes of the 99% of Turks who are Muslims and a compromise has been reached. The Muslim Sabbath is Friday which technically starts at sunset on Thursday. Shops and businesses remain open but mosques and baths (Hamams) will be busier on Friday than during the rest of the week. Sunday is the secular Sabbath and some, but not all, shops will close. Confusingly enough most museums will have a different day on which they're closed, often Monday.

Major Festivals

Ramazan - A period of fasting, taken seriously by a lot of people. Even casual Muslims will often give up drinking or smoking for this 30 day period when the devout will refrain from eating or drinking between sunrise and sunset. When people do break the fast they like to do so in style and many restaurants (especially in the big international hotels) will cater to the fasters and put on lavish menus with a traditional focus.
As a non Muslim you'll find that a little sensitivity during this time is probably a good idea. In rural or conservative areas of the country you may find open restaurants a little scarce but in the cities life goes on pretty much as usual. Wherever you are it's a little rude to eat in the streets etc. The plus side is that you can get the excellent pide , a flat bread, almost anywhere and it's very tasty.

Seker Bayram follows Ramazan. An important family holiday and a difficult time to travel as many people will spend at least part of this 3 day festival with relatives. If you're planning to travel over this period make sure you've booked both ways in advance. It's a time for giving sweets and presents to children and friends and generally celebrating the end of the fasting period.

Kurban Bayram - If you're familiar with the opening verse of Bob Dylan's 'Highway 61' then you'll know a little about the origins of Islam's most important religious holiday. The ram that Moses ended up sacrificing in lieu of his son Isaac is probably not popular amongst Turkey's livestock, many of which meet their respective makers during the 4 day festival.
Kurban, or sacrifice, Bayram is an important affirmation of one of the key tenets of Islam, shared social responsibility. Families who can afford to sacrifice an animal will do so and there is a complex code stipulating how the carcass should be distributed amongst friends, family and charitable concerns. It's a major public holiday and many shops and businesses will close, perhaps for a week. The burden on the transport system is severe and the newspapers will publish a head count of road traffic mortalities after the holiday. Travelling before the holiday you'll notice the build up sheep, goats and cattle on the outskirts of towns and cities as their owners bring them in to be sold. On the day itself the more squeamish may want to keep out of the way as many animals are despatched in gardens or the street.