Fall: Meet the Season with Two Names

Fall Equinox Dates and Seasonal Weather

Close up of autumn leaves in park
Earl Richardson/EyeEm/Getty Images

Fall is known for its cooler air temperatures and leaf peeping excursions, but there's much more to know about the season that marks the transition from summer to winter.

When is Fall?

Here in the United States, the Labor Day holiday is considered the unofficial end of summer and the start of the fall season. But fall isn't officially here until the fall equinox, which occurs every September 22 or 23 in the Northern Hemisphere (March 20 in the Southern Hemisphere).

It ends with the arrival of the winter solstice in late December.

When is the 2016 fall equinox? 

The below table lists fall equinox dates up to the year 2020. Keep in mind, these are the autumn start dates you'll see marked on your calendar. If you want to celebrate autumn like a true meteorologist, you can celebrate its start on September 1.

Meteorological autumn not only begins earlier than calendar autumn, but it ends sooner too. It lasts for the 3-month period of September, October, and November (March, April, May in the Southern Hemisphere) and ends on November 30 (May 31).

YearNorthern HemiSouthern Hemi
(Astronomical) Fall Equinox Dates
201523 September20 March
201622 September20 March
201722 September20 March
201823 September20 March
201923 September20 March
202022 September20 March

Fall's Cool and Crisp Weather

After enduring the heat of summer, fall's considerably cooler temperatures are a welcome change.

In addition to cooler air, these weather phenomena are also characteristic of the season:

We now know when fall begins and what weather it typically brings, but what is it exactly that happens on the equinox that spells a change in weather?

The Science of Fall

On the fall equinox, the sun’s direct rays strike along the equator (0° latitude) and Earth’s axis is equidistant (it isn't tilted toward or away) from the sun. While this is also true of the spring equinox, the difference in spring weather versus fall weather comes from how our planet faces the sun on these two equinox dates. Since Earth travels eastward around the sun, on the autumnal equinox, the Northern Hemisphere is transitioning from direct to indirect sunlight (that is, we experience cooling temperatures).

The Return of Standard Time (and that Coveted Extra Hour of Sleep)

As early as late August, you may notice that the mornings aren't as brightly lit as they were at summer's start, and that the evenings are getting darker earlier. This is because during fall, the days become increasingly shorter and nighttime arrives noticeably earlier. To coordinate our daily lives with this change in daylight/nighttime we adjust our time clocks accordingly and "fall back" (gain an hour) as we switch from Daylight Saving to Standard Time.

See Also: How to tell "Z time" like a meteorologist

Do You Call it "Fall" or "Autumn"?

Have you ever noticed that fall is the only season that has two names -- "fall" and "autumn"?

The use of "autumn" dates back to the late 14th century when it was adopted into the English language from the French automne. The term "fall," which refers to the dropping of tree leaves at this time of year, appeared around the 17th century. While both titles have been used since the 18th century, "fall" is thought to be more popular in the United States thanks to its younger, more poetic feel at a time when the English language was being spread to the American continent. Back in Britain, however, the more traditional "autumn" won out.

Which do you say, and does what you call it match where you're from? Leave a comment on our Facebook or Twitter page and let us know!

Resources & Links:

"Why Does Fall/Autumn Have Two Names" LiveScience.com. 2 October 2012. Retrieved 30 August 2015.