What time of the day should my iPhone 5s arrive in the mail?

I'm getting an iPhone 5s either today or tomorrow either from UPS or FedEx. I would like to know, since it is a 16GB, when would they drop it off? 5pm maybe?

No way to know. It will depend on which carrier and what route they take. Driver routes change every day based on the packages they are delivering that day. You might receive a package one day at 10AM and the next time it comes at 3 PM.