Every fourth year unless it's the end of a century except when divisible by 400

Rotation and orbit and lunar arc

are out of step and do not keep

their timing synched to a common mark

and thus we have this silly leap.

Leap Day

A year is three-sixty-five and a fourth
so every fourth year we must add in a day.
But our question, up here in the ice-bucket north:
did it have to be put into Februaray?