I am trying to automate response to requests that are coming in over the weekends and outside of the regular work hours of 9 to 17:00. 

I have tried using the Work flow Rules but the criteria for time requires date and time to be specific, which I do want to avoid. Same thing happens when I try to add the weekend response as well. 

Is there a way to add auto response to a ticket (comes in either via e-mail or web form) that would include a message that the request is out side of office hours?

Thanks in advance for the help.

Darius