Question: is it the 12 month?
Answer: A year is divided into 12 months in the modern-day Gregorian calendar. ... Each month has either 28, 30, or 31 days during a common year, which has 365 days. During leap years, which occur nearly every 4 years, we add an extra (intercalary) day, Leap Day, on 29 February, making leap years 366 days long.