The Christmas Day in Russia is always celebrated at night from the 7th of January to the 8th of January (in Russia there is Orthodox Christmas).
Are the prepositions I've used correct? The intended meaning is that the celebrations take place at night that starts at the end of the day of the 7th of January.
Christmas Day in Russia is celebrated from the evening of 7th January until midnight the following day.
That's the best I can do on the information you have given.