which months in the year have 31 days
The Gregorian calendar has four months with a length of 30 days and seven months that are 31 days long. February is the only month that is 28 days long in common years and 29 days long in leap years.he Gregorian calendar and the Julian calendar both consist of the following twelve months: 1  January - 31 days. 2  February - 28 days; 29 days in Leap Years. 3  March - 31 days. 4  April - 30 days. 5  May - 31 days. 6  June - 30 days. 7  July - 31 days. 8  August - 31 days. 9  September - 30 days. 10  October - 31 days. 11  November - 30 days. 12  December - 31 days.