Thursday November 21, 2019

United States flag Autumn 2024 in United States


Maple leaves in fall showing their red color.
September 2024
Su Mo Tu We Th Fr Sa
12

Labor Day
Monday September 2
(4 years, 9 months, 12 days)

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8

Grandparents Day
Sunday September 8
(4 years, 9 months, 18 days)

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151617

Constitution Citizenship Day
Tuesday September 17
(4 years, 9 months, 27 days)

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22

Autumn
Sunday September 22
(4 years, 10 months, 1 day)

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Autumn Starts: Sunday, Sep 22 8:43 am EDT

Autumn Ends: Saturday, Dec 21 4:20 am EST

Region: Virginia/United States

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Astronomical Fall Dates


The first day of autumn often called fall (September equinox or autumnal equinox) is when the sun shines directly on the celestial equator passing from north to south and the length of day and night are almost the same. This is referred to as astronomical autumn or the September equinox.


Astronomical autumn starts at different times around the planet because of the different time zones as related to Coordinated Universal Time (UTC, same as Greenwich Mean Time based on the Royal Observatory in Greenwich, London [1]). For countries located west of UTC your autumn will start earlier than countries located east of UTC.


Astronomical and Meteorological Autumn

Astronomical Autumn is determined by the changing positions of the earth relative to the sun giving us the solstices and equinoxes. Seasons are caused by the tilt of the earth on its axis by 23.5 degrees. The tilt of the earth does not change as it goes around the sun so in the Northern Hemisphere the earth is tilted toward the sun in June and away from the sun in December[2]. When the sun is over the equator you have the equinoxes and when the sun is over the Tropic of Cancer in the most northern position you have the Summer solstice and conversely when the sun is over the most southern position over the Tropic of Capricorn you have the Winter solstice. The September equinox occurs in the Northern Hemisphere between the dates of September 21 to 23 followed by the Winter solstice - December 20 to 23 and then the March equinox - March 19 to 21 and then finally the Summer solstice - June 20 to 22. The United States, most of North America, Europe and many countries in the Northern Hemisphere use astronomical autumn to determine when autumn (fall) season officially starts and ends.


Meteorological Autumn is determined by the annual temperature cycles and the Gregorian calendar. Meteorological autumn starts September 1st in the Northern Hemisphere and lasts 3 months (September, October, and November) with Winter Season (December, January, and February) and Spring Season (March, April, and May) and finally Summer Season (June, July, and August). Australia and New Zealand in the Southern Hemisphere use meteorological autumn thus the months of March, April and May to determine their autumn season.


Autumn and the harvest go together with many cultural festivals centered around harvesting the fields during the autumn season. Thanksgiving is one of the more popular American federal holidays that celebrate the harvest with family and friends getting together to eat turkey and more.



References:
1.”Greenwich Mean Time” - Wikipedia, wikipedia.org.
2.”Autumn and Earths tilt” - National Weather Service, weather.gov.



Autumn
Name(s):Autumn, Fall, Autumnal Equinox, September Equinox
Type:Season
When:When:Astronomical - Sep 21st to 23rd
Meteorological - September, October, and December
(Northern Hemisphere)

Dates for Autumn

YearAutumn StartsAutumn Ends
Autumn 2018 Saturday, September 22 2018Friday, December 21 2018
Autumn 2019 Monday, September 23 2019Saturday, December 21 2019
Autumn 2020 Tuesday, September 22 2020Monday, December 21 2020
Autumn 2021 Wednesday, September 22 2021Tuesday, December 21 2021
Autumn 2022 Thursday, September 22 2022Wednesday, December 21 2022
Autumn 2023 Saturday, September 23 2023Thursday, December 21 2023


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