Summer solstice

For other uses, see Summer solstice (disambiguation).
Summer solstice
Sunrise at Stonehenge in England during the summer solstice in the Northern Hemisphere
Also calledMidsummer; the Longest Day; the Shortest Night; Estival solstice
Observed byVarious cultures
TypeCultural, astronomical
SignificanceBeginning of lengthening nights and shortening days
DateJune 20, June 21, or June 22
(Northern Hemisphere)
and December 20, December 21, December 22, or December 23
(Southern Hemisphere)
UT date and time of
equinoxes and solstices on Earth[1][2]
event equinox solstice equinox solstice
month March[3] June[4] September[5] December[6]
year day time day time day time day time
2019 20 21:58 21 15:54 23 07:50 22 04:19
2020 20 03:50 20 21:43 22 13:31 21 10:03
2021 20 09:37 21 03:32 22 19:21 21 15:59
2022 20 15:33 21 09:14 23 01:04 21 21:48
2023 20 21:25 21 14:58 23 06:50 22 03:28
2024 20 03:07 20 20:51 22 12:44 21 09:20
2025 20 09:02 21 02:42 22 18:20 21 15:03
2026 20 14:46 21 08:25 23 00:06 21 20:50
2027 20 20:25 21 14:11 23 06:02 22 02:43
2028 20 02:17 20 20:02 22 11:45 21 08:20
2029 20 08:01 21 01:48 22 17:37 21 14:14
Earth during the summer solstice in June 2017

The summer solstice or estival solstice[i] occurs when one of Earth's poles has its maximum tilt toward the Sun. It happens twice yearly, once in each hemisphere (Northern and Southern). For that hemisphere, the summer solstice is the day with the longest period of daylight and shortest night of the year, when the Sun is at its highest position in the sky. At either pole there is continuous daylight at the time of its summer solstice. The opposite event is the winter solstice.

The summer solstice occurs during the hemisphere's summer. In the Northern Hemisphere, this is the June solstice (20, 21 or 22 June) and in the Southern Hemisphere, this is the December solstice (20, 21, 22 or 23 of December). Since prehistory, the summer solstice has been a significant time of year in many cultures, and has been marked by festivals and rituals. Traditionally, in temperate regions (especially Europe), the summer solstice is seen as the middle of summer and referred to as midsummer; although today in some countries and calendars it is seen as the beginning of summer.

On the summer solstice, Earth's maximum axial tilt toward the Sun is 23.44°.[7] Likewise, the Sun's declination from the celestial equator is 23.44°.

Diagram of Earth's seasons as seen from the north. Far left: summer solstice for the Northern Hemisphere. Front right: summer solstice for the Southern Hemisphere.

Although the summer solstice is the longest day of the year for that hemisphere, the dates of earliest sunrise and latest sunset vary by a few days.[8] This is because Earth orbits the Sun in an ellipse, and its orbital speed varies slightly during the year.[7]

  1. ^ Astronomical Applications Department of USNO. "Earth's Seasons - Equinoxes, Solstices, Perihelion, and Aphelion". Retrieved 2022-08-01.
  2. ^ "Solstices and Equinoxes: 2001 to 2100". AstroPixels.com. 20 February 2018. Retrieved 21 December 2018.
  3. ^ Équinoxe de printemps entre 1583 et 2999
  4. ^ Solstice d’été de 1583 à 2999
  5. ^ Équinoxe d’automne de 1583 à 2999
  6. ^ Solstice d’hiver
  7. ^ a b "The Long Story (USNO explanation)". Archived from the original on 18 June 2017. Retrieved 21 June 2017.
  8. ^ "US Naval Observatory: Sunrise and Sunset Times Near the Solstices". Archived from the original on 18 June 2017. Retrieved 21 June 2017.


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