Ubi
Think about this:
July used to be called SEXtember = 6th month
SEPTember = 7th month
OCTober = 8th month
NOVember = 9th month
DECember = 10th month
Jan = 11th
Feb = 12th
Thats why February was left holding the bag as the shortest month. It a leap year they simply added a day to the “end” of the year.
All this shows how ancient out mesorah is. history of 2500 years ago is reflected in the way we do mitzvos.