Autumnal Equinox 2018

When is the Autumnal Equinox 2018?

What is the Autumnal Equinox?

In the Northern Hemisphere, the moment in time when the Sun stands directly above the equator while crossing from the north to the south is called autumnal equinox (also known as fall equinox, September equinox or southward equinox). It is the moment summer ends and autumn (fall) begins in the Northern Hemisphere (where nearly 90% of the world's population live). For the Southern Hemisphere, it is the vernal equinox (also called spring equinox) as it is the moment winter ends and spring begins.

In the Northern Hemisphere the autumnal equinox occurs every year on September 21 to 23. Occasionally it can also fall on September 21 or 24. The dates given on this page are based on Coordinated Universal Time (UTC), which for practical purposes is equivalent to Greenwich Mean Time (GMT). While the autumnal equinox occurs at the same moment in time all over the world, the date and local time differ from place to place depending on the year and a location's time zone. For locations that are ahead of UTC (further east) it may fall on the day after, and for locations that are behind UTC (further west) it may fall on the day before. To find out the exact date and time of the autumnal equinox 2018 in your area use this seasons calculator.

The autumnal equinox is one of four days (two equinoxes and two solstices) throughout the year that mark the beginning of a new season. The other days are the vernal equinox (beginning of spring), the summer solstice (beginning of summer) and the winter solstice (beginning of winter).

The word "equinox" is derived from Latin and means "equal night". On the day of an equinox, day and night are of approximately equal length all over the world, as the Earth's rotational axis is neither tilted away from nor towards the Sun. At all other times the length of day and night will be different.


The exact moment of the autumnal equinox through the centuries

Graph demonstrating the movement (caused by leap shifting) of the exact moment of the autumnal equinox between 1900 and 2520. X axis (bottom, horizontal): Calendar years, Y axis (left, vertical): day in September (21 to 23).

In a non-leap year, the moment of the autumnal equinox is about 5 hours 49 minutes after that moment in the previous year (in UTC), and in a leap year it is about 18 hours 11 minutes before that moment in the previous year, as can be seen in this graph. In this way the time of the autumnal equinox constantly shifts back and forth so it always stays around September 21 to 23. This four year cycle is clearly visible in the graph.

To adjust for the gradual movement backwards on the calendar (as visible for the period 1900 to 2099), in years divisible by 100 (1900, 2100, 2200, 2300 and 2500 on the graph), which should be leap years as they are divisible by 4, the leap day is omitted (except when they are divisible by 400, eg. 2000 and 2400) and the moment of the autumnal equinox moves forward in time compared to the same moment in the year before.


For more information see September equinox on Wikipedia.

When is the Autumnal Equinox 2019?

Dates for the Autumnal Equinox from 2013 to 2023

The next occurrence of the Autumnal Equinox is marked in red.

When is ...?	Date	Day of the week	Days away
Autumnal Equinox 2013	September 22, 2013	Sunday	1794 days ago
Autumnal Equinox 2014	September 23, 2014	Tuesday	1428 days ago
Autumnal Equinox 2015	September 23, 2015	Wednesday	1063 days ago
Autumnal Equinox 2016	September 22, 2016	Thursday	698 days ago
Autumnal Equinox 2017	September 22, 2017	Friday	333 days ago
Autumnal Equinox 2018	September 23, 2018	Sunday	in 33 days
Autumnal Equinox 2019	September 23, 2019	Monday	in 398 days
Autumnal Equinox 2020	September 22, 2020	Tuesday	in 763 days
Autumnal Equinox 2021	September 22, 2021	Wednesday	in 1128 days
Autumnal Equinox 2022	September 23, 2022	Friday	in 1494 days
Autumnal Equinox 2023	September 23, 2023	Saturday	in 1859 days
Data provided 'as is' without warranty

Dates of the Autumnal Equinox 2018 and surrounding years as downloadable image file

Calendar templates 2018 for Word, Excel & PDF

2018 calendar as templates for Word, Excel & PDF A selection of calendar templates for 2018 in landscape and portrait orientation and with US federal holidays, suitable for a variety of applications. 2018 calendar templates for Word 2018 calendar templates for Excel 2018 calendar templates for PDF

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US federal holidays New Year's Day Martin Luther King Day Presidents' Day     (Washington's Birthday) Memorial Day Independence Day Labor Day Columbus Day Veterans Day Thanksgiving Day Christmas Day Australian holidays ANZAC Day The seasons Spring Vernal equinox (spring equinox, March Equinox) Summer Summer solstice (June solstice) Autumn / Fall Autumnal equinox (fall equinox, September equinox) Winter Winter solstice (December solstice)

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