Most Christians celebrate Christmas on December 25th. However, some people celebrate Christmas in January due to cultural and religious differences. In some countries, like Russia and Ukraine, Christmas is celebrated on January 7th according to the Julian calendar. Additionally, some Orthodox Christians also celebrate Christmas on January 6th or 7th, depending on the region. In some cultures, such as in Ethiopia, Christmas is celebrated on January 7th, but it's observed as a 13-day festival called Ganna.