Thirty days hath September,
April, June, and November.
All the rest have thirty-one
All except the second one
Which alone has tweny-nine
When comes Leap Year in its time.
Every four years, I try to remember why we do this Leap Year thing. It's the ancient Egyptians who figured out that the the calendar-year and the wonky Earth-year don't match up. It takes 365.2422 days for the Earth to orbit the Sun. That's 365 days, 5 hours, 48 minutes, and 46 seconds to be exact. So, Julius Caesar and his astronomer Sosigenes came up with a 365 day calendar with months alternating between 30 and 31 days. An extra day was sometimes added to the last month of the year which was February.
What's more interesting is why February is such a short month now. Julius Caesar's calendar had a 30 day February. When Caesar Agustus became emperor, his month (August) only had 30 days while his predecessor Julius' month ( July) had 31. The Senate decided that the two months should be equal and took a day for August so it would equal July. To even things out, February got the short end.
Here's how I like to think of things:
Thirty days hath September.
All the rest I can't remember.
The calendar hangs on the wall;
Why bother me with this at all?
"Leap year is never a good sheep year." - Old Scottish saying (Baah)