Autumn, also known as fall in North American English, is one of the four temperate seasons.
The date of the beginning of autumn varies according to climate, tradition and culture, but when it is autumn in the Northern Hemisphere, it is spring in the Southern Hemisphere, and vice versa.
In the Northern Hemisphere autumn lasts from the autumnal equinox (September 22 or 23) to the Winter Solstice (21 or 22 December). In the Southern Hemisphere, autumn lasts from March until June.
The 1st day of autumn 2017 in Northern Hemisphere will be on Friday, September 22. And the last day of autumn 2017 will be on Thursday, December 21.
The reason the equinoxes and solstices don’t always come on the same day is that Earth doesn’t circle the sun in exactly 365 days.
The first day of autumn, the autumnal equinox, has 12 hours of daylight and 12 hours of darkness. The term equinox comes from the Latin words aequus, meaning equal and nox, meaning night.
Autumn begins when the center of the sun crosses Earth’s equator. As Earth continues its path around the sun, days become shorter and nights become longer.
The Earth’s orbit around the Sun has very little effect over the Seasons on Earth. Instead, it the tilt of Earth’s rotational axis, which is angled at around 23.5 degrees, that creates seasons.
Autumn is derived from the French, which came from the Latin autumnus, the Roman name for this season.
While Americans typically use the word “fall,” the British use the word “autumn,” though both terms date around the 16th century. Before these terms, the period was called “harvest.”
The word “harvest” comes from the Old Norse word haust, which means “to gather or pluck.” As people moved to the cities, “harvest” fell out of use and city dwellers began to use “fall of the leaf,” which was shortened to “fall.”
One of the most stunning signs of Autumn is the turning of the leaves. Leaves change their wardrobes in response to chilly temperatures and less light (as days begin to shorten); they stop producing chlorophyll, the green pigment that helps leaves capture sunlight to power photosynthesis. As green fades, the leave’s other pigments, such as the orange and yellow of carotenoids shine through. Vibrant red hues are the result of anthocyanins, pigments that are produced in the fall.
In addition to the brilliant colors of fall leaves, the autumn equinox signals another colorful spectacle —
the aurora. According to NASA, autumn is “aurora season” because geomagnetic storms are about twice as frequent as the annual average during the fall.
A “Harvest Moon” is the full moon closest to the autumn equinox. Before artificial lighting, such moonlight was essential to a farmer’s successful harvest.
Association with the transition from warm to cold weather, and its related status as the season of the primary harvest, has dominated its themes and popular images. In Western cultures, personifications of autumn are usually pretty, well-fed females adorned with fruits, vegetables and grains that ripen at this time.
In Greek mythology, Autumn began when Persephone was abducted by Hades to be the Queen of the Underworld. In distress Persephone’s mother, Demeter (the goddess of the harvest), caused all the crops on Earth to die until her daughter was allowed to return, marking Spring.
Autumn, especially in poetry, has often been associated with melancholia. The possibilities of summer are gone, and the chill of winter is on the horizon. Skies turn grey, the amount of usable daylight drops rapidly, and many people turn inward, both physically and mentally.
Meteorologists (and most of the temperate countries in the southern hemisphere) use a definition based on months, with autumn being September, October and November in the northern hemisphere, and March, April and May in the southern hemisphere.
While most foods are harvested during the autumn, foods particularly associated with the season include pumpkins (which are integral parts of both Thanksgiving and Halloween) and apples, which are used to make the seasonal beverage apple cider.
According to seasonal patterns of relationships in Facebook profiles, autumn is the time when more singles change their status to “In a Relationship” or “Engaged” than the yearly average.
Levels of testosterone in both men and women are at their highest in the fall. Scientists speculate the surge may be a result of ancient mating instincts or that decreasing daylight somehow triggers it.
No film with autumn in its title has won an Oscar. Spring, summer and winter have one each.
Since 1997, Autumn has been one of the top 100 names for girls in the United States.
A study in the Journal of Aging Research found that babies born during the Autumn months are more likely to live to 100 than those born during the rest of the year.
Many animals begin to prepare for the winter by storing food in their nests and dens or fat on their bodies.
Many birds prepare for winter migration during the fall.