A leap year is because 1 year isn’t exactly 365 days. It’s something like 365.24.
You may be thinking of a sidereal day which is around 23 hours 56 minutes. That’s the time it takes the Earth to complete a rotation, but since the Earth orbits the sun it isn’t long enough to put the sun at the same spot in the sky.
I thought every day was shorter then 24 hours, and that is why we have leap year.
A leap year is because 1 year isn’t exactly 365 days. It’s something like 365.24.
You may be thinking of a sidereal day which is around 23 hours 56 minutes. That’s the time it takes the Earth to complete a rotation, but since the Earth orbits the sun it isn’t long enough to put the sun at the same spot in the sky.