There is only 1 month of the year with 28 days, February.
Every 4th year, Leap Year, there are no months with 28 days because February has 29 days on leap year.
What is Leap Year?
the world takes approximately 365.25 days to revolve around the sun. So to compensate for that partial day over 365, every fourth year we add an additional day to the calendar and that falls at the end of February.