Question: is 12 o'clock the next day?
Answer: Midnight – and noon – aren't defined as a.m. or p.m. You can talk about 12:01 a.m., and you can talk about 12:01 p.m., but 12 o'clock a.m. and 12 o'clock p.m. mean different things to different people. ... In that system, tonight's midnight is the first moment of tomorrow.