Weather Tidbits: Leap Years

This Weather Tidbits will discuss about leap years and why we have them in the first place. A leap year is a 366 day year that adds an extra day to February compared to a regular 365 day year. The main reason why leap years exit is due to the fact that Earth does not actually take exactly 365 days to revolve around the sun. This is a rounded number of the actual 365.242190 (~365.25) days that one revolution around the sun takes. We’ll label this as the sidereal year. If we do not account for the eventual accumulation of time from the sidereal year, the seasons will begin to shift over hundreds of years. For example, in about 700 years, the first day of summer would be in December. Thus, we add an extra day to the calendar year approximately every four years to compensate for this.

However, this does not completely solve the issue because the difference between the sidereal year and the calendar year is not exactly 24 hours. It’s actually 23.26 hours. Not taking this other factor into account would lead to yet another seasonal shift as the years progress. The solution here is to skip years that are divisible by 100 but not by 400 that would otherwise be normal leap years. Examples of years like this are 1700, 1800, and 1900. The next year to fall into this category would be the year 2100.