The phrase "the night before" means the evening and night preceding a specific day or event. People use it to frame prep, reflection, jitters, or rituals tied to the next day.
Yeah, that came out of a reading. It was great. It's such a fun crew to be with, and we all went out the night before and that really encouraged us to go out and get drunk. John Leguizamo
I received an award for 25 million in [album] sales the night before the bus accident [in 1990]. Gloria Estefan
I have never had problems sleeping the night before a race. Bobby Rahal
Misers get up early in the morning; and burglars, I am informed, get up the night before. G. K. Chesterton
I don't need a baby growing inside me for nine months. If I'm going to feel nauseous and achy when I wake up, I want to achieve that state the old-fashioned way: getting good and drunk the night before. Ellen DeGeneres
Wait for the night before saying that the day has been beautiful. Bengali Proverb