Family Day is a provincially recognized statutory holiday in BC but it is not recognized as a Federal stat holiday.
Here is a link to federally recognized statutory holidays: https://www.canada.ca/en/revenue-agency/services/tax/public-holidays.html
This means that your payroll source deductions for January 2021 are due TODAY if you are a monthly filer.
Please make sure to get your payments in on time to avoid any interest or penalties.