How to create a promotion that will be available within a specific period of time?
Magento offers the From - To setting for making a promotion temporary. To configure the start and end day of your promotion, navigate to Marketing → Promotions → Cart Price Rules, choose the rule or create a new one and set the time period:
Magento Commerce
The Commerce edition users can schedule various store changes and events, including promotions. For that, open the required rule or create a new one in Marketing → Promotions → Cart Price Rules, click the Save and Continue Edit button and then Schedule New Update:
Set the needed schedule using the calendar: