You can check whether the macro triggers at all by looking in the Engine.log file the next morning.
If the Mac is asleep, nothing will happen, no macros will fire.
If the Mac is awake, the macro should fire, however if the screen is asleep, screen saving or screen locked, many facilities will be blocked by the system. Things like Execute Script should be fine, but things that try to do UI will fail.
You might like to do something like this:
Trigger at 6pm
Pause Until IDLE() > 60*5 (less than your display sleep time)
Alert “Run Macro?” Timeout 1 minute without aborting the macro
Do stuff
Of course, if you cancel the macro, then the actions will not run at all.