Equinox
UTC date and time of solstices and equinoxes[1]
Equinox
Mar
Solstice
June
Equinox
Sept
Solstice
Dec
year
day
time
day
time
day
time
day
time
2004
20
06:49
21
00:57
22
16:30
21
12:42
2005
20
12:33
21
06:46
22
22:23
21
18:35
2006
20
18:26
21
12:26
23
04:03
22
00:22
2007
21
00:07
21
18:06
23
09:51
22
06:08
2008
20
05:48
20
23:59
22
15:44
21
12:04
2009
20
11:44
21
05:45
22
21:18
21
17:47
2010
20
17:32
21
11:28
23
03:09
21
23:38
2011
20
23:21
21
17:16
23
09:04
22
05:30
2012
20
05:14
20
23:09
22
14:49
21
11:11
2013
20
11:02
21
05:04
22
20:44
21
17:11
2014
20
16:57
21
10:51
23
02:29
21
23:03
2015
20
22:45
21
16:38
23
08:20
22
04:48
2016
20
04:30
20
22:34
22
14:21
21
10:44
2017
20
10:28
21
04:24
22
20:02
21
16:28
An equinox occurs twice a year, when the tilt of the
Earth’s axis is inclined neither away from nor towards
the Sun, the Sun being vertically above a point on the
Equator. The term equinox can also be used in a broader
sense, meaning the date when such a passage happens.
The name "equinox" is derived from the Latin aequus
(equal) and nox (night), because around the equinox, the
night and day are approximately equally long. It may be
better understood to mean that latitudes +L and -L north
and south of the equator experience nights of equal
length.
The word is also used for the same event happening
on other planets and in setting up a celestial coordinate
system; see equinox (celestial coordinates).
At an equinox, the Sun is at one of two opposite
points on the celestial sphere where the celestial equat-
or (i.e. declination 0) and ecliptic intersect. These points
of intersection are called equinoctial points: the vernal
point and the autumnal point. By extension, the term
equinox may denote an equinoctial point.
An equinox happens each year at two specific mo-
ments in time (rather than two whole days), when there
is a location on the Earth’s Equator where the centre of
the Sun can be observed to be vertically overhead,
occurring around March 20/21 and September 22/23
each year.
Illumination of the Earth