Triaoraphobia

Triaoraphobia is the fear of 3:00 AM. This fear is often caused by the fact that 3:00 AM is known as the witching hour and suffers may think that ghosts will haunt them at 3:00 AM. They would feel normal in the morning and the afternoon, but may start to feel some dread when evening begins, and may feel even more dread once nighttime starts.

The phobia's name is derived from the Greek words for "third" and "hour" (tris, hora).