In Russia you may designate shocked and not think twice when the same celebration in different time. It is because they have a calendar or the Julian Calendar Julius already applied since the time the ancestors of Russia.
This unique celebration of happen for example when the new year the citizens of Russia celebrate the moment of the turn of the year twice. Exactly on 1 January and 14 January. Or when Christmas is celebrated on January 7, when Christmas celebrations usually falls on December 25.