Contrary to what lots of foreigners think, this coming Friday, September 16, Mexican Independence Day is celebrated and not on 5 de Mayo. This will be an official holiday countrywide, which means that you should expect most banks and government offices to be closed.
Employees will get the day off by law, and if they are called to work that day, they must be paid double their usual salary.
The Mexican federal work law states that any employee that has to work on an official holiday has to be paid double, and if said holiday falls on a Sunday, they have to be paid triple their usual salary. This year the only holiday that needs be paid triple is December 25.