Corpse answered that :
Frozen II should be at ¥5.8/5.9 billion ($53/54 million) after Sunday. Its third weekend looks headed for a 30% or so decline (right around ¥1 billion), which is fine considering how strong its second weekend was, and expected given last Sunday was a national discount ticket day.
There's not really a "Winter Break/Holiday" in Japan. New Year's Eve and New Year's Day begin what's simply called "New Year Week", where all schools and business are closed from January 1st-3rd (known as the "Bank Holidays"). The last few days (last couple in December) leading up to New Year's Day tend to be a little stronger than normal, but not of holiday strength. Still, the week is one of the three strongest for the box-office in the market.
For 2020, that means Wednesday-Friday (Jan. 01-03) will be very strong, especially Wednesday, and will probably double or even triple the neighboring weekend grosses. The following weekend (Jan. 04-05) will also be quite strong. January 6th onward will be back to normal.