Orthodox Christmas is January 7th.

I found an interesting article from a perspective from other parts of the world if you want to read about how, who, when, why & where.

Why do many Orthodox Christians celebrate Christmas in January?

https://embraceme.org/blog/orthodox-christmas

Description with video is below:

It's time for our annual daily posting of Russian Orthodox Cathedrals until Orthodox Christmas. 

The first of this year is the Main Cathedral of the Russian Armed Forces (Cathedral of the Resurrection of Christ), Главный храм Вооружённых сил России (Храм Воскресения Христова).

The Resurrection of Christ Cathedral, is a Russian Patriarchal cathedral dedicated to the 75th anniversary of victory in the Great Patriotic War and the military feats of the Russian people in all wars. Situated in Patriot Park, Odintsovsky District, Moscow Oblast, the cathedral was constructed through a combination of donations and funds from the Moscow city government and the Moscow Oblast. Consecrated as part of the 75th-anniversary celebrations of the Soviet victory in World War II, the cathedral houses an exhibition chronicling the history of the Russian state and its armed forces.

Completed on May 9, 2020, marking Victory Day, the cathedral was consecrated on June 14 and officially opened on June 22, 2020—coinciding with the Day of Remembrance and Sorrow, commemorating Germany's invasion of the Soviet Union in 1941. The opening ceremony was led by Father Oleg Ovcharov, the head of the Russian Orthodox Synod’s new Armed Forces Liaison Department.

It stands as a symbol of spiritual strength and commemoration of the feats of Russian military personnel. This majestic cathedral, crowning the Patriarch's Bridge in Moscow, has become an integral part of the country's religious and cultural heritage. Constructed with wise attention to detail, the Resurrection of Christ Cathedral offers devotees a place of inspiration and worship, serving as a venue to pay homage to those who defend the homeland. The cathedral's magnificent architecture blends with its profound religious and military significance, making it a meaningful symbol in the history and culture of Russia.