How can I get my audio to only play at night time?

I need a certain song to play at night time to add some character into night time instead of just walking around dully.

http://wiki.roblox.com/index.php?title=API:Class/Lighting

local on = false
while wait() do -- make a loop of some sort
if on then return '' end
if GetMinutesAfterMidnight()  > 1 then
--[[ stop any other songs playing OR tween fade it --]]
song:Play()
end
end