Official comment
Hey, yeah.. this would be a cool little feature. For now, I've created a campaign for you that you can use to the same effect.
Add this campaign to your account, set your business hours in the condition, and publish the campaign.
Then, in any other campaign, to pause the contact until you're open, simply use an 'Add to Campaign' element and add them to this Campaign. They will pause on that 'Add to Campaign' element until they reach the 'end' in this campaign, which will happen when your business opens again.
Give it a shot!
This is a good use-case, and I'll explain how this works on next week's Training Tuesday on Facebook.
Log in to your Ontraport account, and then click this link to get my template campaign: https://app.ontraport.com/receivers/marketplace.php?key=13102&hash=b25Sang4NEl2dWMwVQ==&ref=491836
Cheers!