You can set up category availability on your store menu. This will be useful if you want to serve some items only on specific days and times like happy hour from 3-5pm on weekdays or brunch from 9-11am on weekends.
Simply go to,
Stores > Edit Menu > Click on Pen Icon (beside Category) > Availability
Untick 'Category always available' so you can set up Availability.
Untick 'Open 24 hours' for the days you want the category to be available then set the preferred time.
If you want certain categories open on weekdays only for example, make sure you tick 'Closed' on Saturday and Sunday.
Don't forget to click on Save changes