A short poem from a book of poems called “POEMS: Every Child Should Know” by “The What-Every-Child-Should-Know-Library”. This is a song and memory aid for children, which I remember from my youth and which I thought was still useful today.
Thirty days hath September,
April, June, and November;
February has twenty-eight alone.
All the rest have thirty-one,
Excepting leap-year—that’s the time
When February’s days are twenty-nine.