I assume that your branches work the same schedule every week, but different hours on different days. If so, you have two possible solutions.
The "all encompassing" solution is to store open and close times by calendar day. This allows you to easily deal with holidays, summer/winter hours, and special events (such as a branch being open late on the first or the third of every month). It uses more disk (rows), but it is very simple and it allows you nearly infinite flexibility.
The "week with exceptions" allows you to record a "standard" week schedule, then only record the days that are non-standard. This is a bit more complicated, but it uses a lot less storage.
The "week without exceptions" allows you to store one row with branch, day-of-week, open time, and close time. This is very efficent in terms of space, but doesn't allow for exceptions (no holidays, etc).
The "same schedule every day" records branch, open time and close time. It assumes that your branch observes the same schedule every day with no exceptions. This is what I think that dportas was discussing.
-PatP