Thirty Days Hath September

Thirty days hath September is a traditional English mnemonic rhyme, of which many variants are commonly used in English-speaking countries to remember the lengths of the months in the Julian and Gregorian calendars. Here is one version of the rhyme attributed to Mother Goose:

Thirty days hath September,

April, June, and November.

All the rest have thirty-one,

Excepting February alone,

And that has twenty-eight days clear,

And twenty-nine in each leap year.

Other sources list the Mother Goose version differently:

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.