Time of day ranges from 0.00 to 24.00. (24.00 = 0.00 game time)
Time of day turns to "morning" at 6.00, "noon" at 12.00, and night at "18.00".
For example:
-
Game - The in-game time of day becomes Equal to 7.00
It takes a real value. This trigger will fire at 7:00 A.M. (game-time)

If it still doesn't work, then post your code and there is probably something else happening.