At an ungodly hour
Definition 1 of 1
Pro Tip 1/3Impolite Timing
Calling or arriving 'at an ungodly hour' may suggest disregard for others' sleep or routines. 
Sorry for calling you at an ungodly hour, I forgot the time difference.
Pro Tip 2/3Exaggerated Expression
The phrase is often used hyperbolically to describe times that are simply inconvenient. 
I have to leave at an ungodly hour to catch my flight at dawn.
Pro Tip 3/3Informal Setting
It's mostly used in casual conversations rather than formal or academic situations. 
We stayed up chatting until an ungodly hour.