Meteorological summer begins Saturday: What does that mean?

When does summer officially begin? It depends on who you ask.

You may have noticed that weather forecasters define seasons differently than the public, with many referring to the season as "meteorological." 

But why do meteorological and astronomical seasons begin and end on different dates? 

According to scientists, there is a reason. 

What is a meteorological summer?

The meteorological seasons are based on the annual temperature cycle, according to NOAA’s National Centers for Environmental Information. 

People visit Clearwater Beach, Florida. (Credit: Mike Ehrmann/Getty Images)

Therefore, meteorologists and climatologists break the seasons down into groupings of three months based on the annual temperature cycle, as well as our calendar. 

When does meteorological summer start?

Meteorological summer includes the full months of June, July and August. 

This means, meteorological summer starts on June 1 of every year and lasts through Aug. 31 every year.  

Astronomical summer explained

Meanwhile, astronomical seasons, such as the dates you see on a yearly calendar, are based on the position of Earth in relation to the sun.

The natural rotation of Earth around the sun forms the basis for the astronomical calendar, in which we define seasons with two solstices and two equinoxes. 

RELATED: Google Flights says these are the top summer travel destinations of 2024

In the Northern Hemisphere, the summer solstice falls on or around June 20 or 21. 

Because Earth actually travels around the sun in 365.24 days, an extra day is needed every fourth year, creating what is referred to as Leap Year, but this is also what causes the exact date of the solstices and equinoxes to vary. 

When is the first day of summer?

The first day of summer coincides with the summer solstice – or longest day of the year — in the Northern Hemisphere. 

This is also the day when the sun reaches its highest and northernmost points in the sky. 

This year, the first day of summer lands on Thursday, June 20, 2024. 

Hot temperatures expected

Meteorological summer begins June 1, and this year forecasters are predicting warmer-than-average temperatures for much of the U.S.

According to NOAA’s Climate Prediction Center, the summer outlook depicts elevated odds for above-normal monthly mean temperatures for most of the U.S. 

"The overall outlook for the weather pattern suggests that the majority of the lower 48 is going to have a hot summer," FOX Weather reported.