I realize that Edmonton isn't the biggest market in Canada but it is still considered a major and as such should sound like one 24/7. If you turn on a Toronto station in the middle of the night they still sound big league. Ched overnight newscasts sound worst than any small town station.

You also have to realize that every city is different as well.  I'd say that Torontonians proportionately to stay up a bit longer than Edmontonians.  A good indication of your potential market can easily be done at 3am by driving around and seeing "What's open at this time?"