LANSING, Mich (WLNS) — If you were to take a quick look at your calendar, it would show that the first day of fall starts on Sept. 23, but some people say it starts on Sept. 1.

Why is there a difference? 6 News Meteorologist Kendall Wilson explains in this week’s Weather Wednesday.

Cooler, fall-like temperatures will soon start to settle into the area but the calendar says the first day of fall isn’t until Sept. 23.

Well, that’s the case for astronomical fall but meteorological fall actually started back on Sept. 1. But how and why do we have two different start dates for the same season?

The astronomical season is the one that most people are familiar with; it’s the one that will show up on your calendars and Google whenever you search for “the first date of fall.”

It’s been around for thousands of years and is based on the rotation of the Earth around the Sun.

The Earth’s tilt on its axis is what causes our astronomical seasons. We have the two solstices, which relate to the winter and summer seasons; and two equinoxes which correlate to spring and fall.

Now, the problem that arises with astronomical seasons is that they start halfway through the month, and the duration of the seasons can vary from 89 to 93 days. It’s because of this that meteorological seasons were created. 

With meteorological seasons, it’s based on the yearly temperature cycle as well as our calendar.

So, now we break the seasons down into groups of three months.

For winter, we have December, January and February. Spring has March, April and May, and so on and so forth.

When we think about seasons it makes it easier to calculate yearly, seasonal and monthly averages, because the start and length of the seasons are more consistent. 

But deciding which of these two uses is up to you.

If you ever find yourself in a conversation and one person says fall starts on Sept. 1 and another says it’s not until Sept. 23 …. Well, they’re both right!