The crack of dawn, or just before it, usually between 1 A.M. and 4 A.M. or 2 A.M. and 5 A.M. * /He stayed up all night when they were expecting their first child; finally, a boy was born in the wee hours of the morning./ Compare: SMALL HOURS.
WEE HOURS
Meaning of WEE HOURS in English
Slang English vocab. Английский сленговый словарь. 2012