Christmas in Iran is known as the Little Feast. For the first 25 days of December, a great fast is observed, during which no meat, eggs, milk, or cheese is eaten.
Iran has a variable climate. In the northwest, winters are cold with heavy snowfall and subfreezing temperatures during December and January.
The time of Islamic festivals is calculated according to local sightings of various phases of the moon and the dates given below are approximations which are subject to change each year.