Hello, and sorry for taking a while to get back to you.
Currently there's no way to do it, but the scheduling feature is being improved to support exactly that. The syntax supported since snapd 2.25 is described in the core configuration options topic,
Per that existing syntax, the dash (-) character separates ranges, and the slash (/) separates independent windows which are summed up. Some examples:
9:00 – Every day starting within 9-10am.
9:00-11:00 – Every day starting within 9-11am.
9:00-11:00/14:00-16:00 – Every day starting within 9-11am and 2-4pm.
I propose we extend this syntax so that in addition to the dash ranges and slashed sets, we add support for the at symbol (@) defining the day of the week in which a set is applied, and the comma (,) separating options within a given day. The weekday would be defined by the English three-letter prefix, potentially suffixed by a number that defines the week within the month.
Some examples of the proposed extensions:
mon-fri@9:00-11:00 – Monday to Friday, starting within 9-11am.
tue,fri@9:00-11:00,14:00-16:00 – Every Tuesday and Friday, starting within 9-11am and 2-4pm.
tue1,tue3@9:00 – Every first and third Tuesday of the month, starting within 9-11am.
What do you think?