Frankenstein's monster was born in the makeshift lab at the hostel of Frankenstein at night.
Step-by-step explanation:
Frankenstein had been doing his dangerous experiments on ife and human form and reproduction in his lab for a long time and as such he had by the time he became successful amassed enough chemical help from his university and had made for himself a makeshift lab in his hostel to do his experiments in.
The night that he succeeded with his experiment is when he is doing it on a windy night in the cold inside his hostel and the monster is born and runs away instantly.