There are seven months in a year that have 31 days. These months are:
January (31 days)
March (31 days)
May (31 days)
July (31 days)
August (31 days)
October (31 days)
December (31 days)
The other months have fewer days:
February has 28 days in a common year and 29 days in a leap year.
April, June, September, and November each have 30 days.
Remember the old rhyme to recall the number of days in each month:
“Thirty days hath September,
April, June, and November.
All the rest have thirty-one,
Except February alone,
Which hath but twenty-eight days clear,
And twenty-nine in each leap year.”