FORT WAYNE, Ind. (WANE) — Meteorological fall begins this Friday. This might have you scratching your head… Does fall actually begin this Friday? In short, no. Fall doesn’t officially begin until September 23rd this year. If that’s the case, then why do we have this and how is it different from the actual season we know?

Let’s start with the biggest difference: Meteorological fall is a season created by scientists while the actual fall season is based on the astronomical timing of the autumn equinox and winter solstice.

Meteorological fall begins every year on September 1st and comes to an end on November 30th. While the dates for the meteorological seasons do not change, the beginning and end date for the autumn equinox changes every single year. This change in timing is caused by the Earth’s elliptical (think more of an oval shape) orbit and the way that the Earth tilts back and forth on its axis. The Earth’s back-and-forth tilt is what causes the change in our seasons! As the Earth tilts forward towards the Sun, we experience spring and summer. When the Earth begins to tilt away from the Sun, we experience fall and winter.

Because the autumn equinox date changes every year, this also means that each season has a different length every year when it comes to the number of days. According to the National Centers for Environmental Information (NCEI), a division of the National Oceanic and Atmospheric Administration (NOAA), astronomical seasons vary between 89-93 days while the meteorological seasons last between 90-92 days. Length is also determined by whether or not we are also in a leap year.

Because the astronomical seasons vary every single year, it was difficult for scientists to properly analyze weather data, especially long-term weather. Long-term data provides an outlook into trends and patterns and provides a “heads up” in many situations. To make it easier on the atmospheric scientists, the meteorological seasons were born!

All meteorological seasons:

  • Winter – December, January and, February
  • Spring – March, April and, May
  • Summer – June, July and, August
  • Fall – September, October and, November

In addition to this, scientists took the pubic into consideration. We typically tend to associate the season of Fall with the months of September, October, and November. We can see this in our data as well as we see temperatures begin to turn cold and the days grow shorter.

This data isn’t useful for scientists, it can help others, too. For example, it allows farmers to look at seasonal outlooks to know how to prepare for drought potential or an unusually cold pattern.

At the end of the day, the meteorological seasons allow your local meteorologists to better analyze seasonal weather patterns and provide you with a better forecast.