You can set your Store retail hours by navigating to  Settings > Website Settings > Website Settings.

In the Store Retail hours Section Here you can:

• Show Hours on the website - YES or NO
• Hours Detail 
  • Simple Hours - This allows you to set your hours for Monday - Friday, Saturday, and Sunday
  • Detailed Hours - This allows you to set your hours for each individual day. 
• Custom Text - allows you to add custom text listed by your hours.