Most ‘feriados’, or public holidays, are fixed in Argentina:
For the following holidays, the day of the holiday moves to the Monday before if it falls on a Tuesday or Wednesday, or to the following Monday if it falls Thursday to Sunday:
A full list of public holidays in Argentina can be found here. Many businesses, and some museums and entertainment venues, close on these days, but it isn’t unusual for restaurants, bars and supermarkets to stay open. Public transport continues to run, even on Christmas Day, but at a reduced frequency.
School holidays in the summer run from the middle of December to the end of February. Winter holidays are two weeks in July.