Soon enough, the oak and sugar maple trees will bloom into fiery beacons of yellow, orange and red.  Turning neighborhood streets into colorful carpets of fallen leaves.  We can already feel the weather changing, cooler mornings have forced students to bring an extra jacket for the morning commute to school.  Shorts have been replaced by leggings and sweatpants, while soon enough sandals and sneakers will be replaced by winter boots.  We hear about the changing of seasons throughout September, but have you ever wondered why there are more than one announcements of autumn?

Scientists use both meteorological and astronomical calendars to determine the seasons each year.  Meteorological fall, which began September 1, 2021, is a more standard method adopted by scientists and the public alike.  Meteorological seasons begin at the same time each year and  last three months, based around yearly temperature cycles.  Meteorological Fall begins in September and lasts through the end of November.  Meteorological seasons have been around since the 1900s, and because we organize our lives and time around the months, has become the preferred and easiest way to determine and keep track of seasons.  

Astronomical seasons, on the other hand, are a much older but less practical method to determine the seasons.  Astronomical seasons are based on the tilt of the earth on its axis, and the changing seasons are marked by the two equinoxes and two solstices.  The fall equinox occurs when the earth is tilted just right, so that the day and night in both the Northern and Southern hemispheres are of equal length.  These two days mark the beginning of spring early in the year, and fall later in the year.  This year’s autumn equinox was September 22, 2021 and technically lasts until the winter solstice in December.

No matter which method you use to determine the seasons, autumn is upon us!  Get ready for falling leaves, corn mazes, haunted houses, and cooler weather.