Question

why February has only 28 days​

Answer 1

This is because of simple mathematical fact: the sum of any even amount (12 months) of odd numbers will always equal an even number—and he wanted the total to be odd. So Numa chose February, a month that would be host to Roman rituals honoring the dead, as the unlucky month to consist of 28 days.

Answer 2

Answer:

Because it is leap year

I am not sure