|February in recent years|
February 31, with regard to the modern Western (revised Gregorian) calendar, is an imaginary date. It is sometimes used for example purposes, to make it clear regardless of context that the information being presented is artificial and not real data. February 30 is sometimes used in the same manner, although there are other calendars that legitimately use February 30.
In an interview with Scott Cawthon, he has said that his birthday is February 31 as a joke while the other person completely has not noticed the fact.