Weather Tidbits: Leap Day & Leap Year

This Weather Tidbits explains why we have a leap day and a leap year. The Earth goes one revolution around the sun every year, which actually equals every 365.2422 days and not 365 days. If we didn’t have a leap year, this will lead to .2422 days or 5.8 hours missed each year and in 100 years, our calendar would be off 24 days; meaning the 1st day of spring would move from March 21st to February 25th. The solution to the problem is adding one day every four years; which leads to a yearly average of 365.25 days, but is the problem solved? Almost, by adding one day every four years; this leads to .0078 days or 11.2 minutes too much each year, and in 100 years, our calendar would be off 18 hours.

This problem is solved when a leap year hopscotch is performed. This is where we skip a leap year if it’s falls on the start of a century; unless that year is divisible by 400. This means that in the year 2000 & 2400 it occurs but not in 1900 or 2100 because it’s not divisible by 400.  This will also explain that February 29th would occur in 2096 and not happen again 8 years later in 2104. This leads to a new yearly average of 365.2425 days; but leaves .0003 days or 25.9 seconds too much year, which would take 3,333 years to be one day off.