When you create a rule or deal in the Campaign Center, you can choose to apply it to specific days, dates and times. For example, you can apply it only in February 2021, on Sundays from 3-5pm.
By default, rules and deals apply anytime.
However, you can click on "At any date and time" to define specific times.
For example, you can apply it during August 2018, Mon-Fri at 12-6pm and Sat-Sun at 3-5pm: