Summer solstice

The summer solstice, also known as estival solstice or midsummer, occurs when one of the 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 when the Sun reaches its highest position in the sky and is the day with the longest period of daylight. Within the Arctic circle (for the northern hemisphere) or Antarctic circle (for the southern hemisphere), there is continuous daylight around the summer solstice. On the summer solstice, Earth's maximum axial tilt toward the Sun is 23.44°. Likewise, the Sun's declination from the celestial equator is 23.44°.

UT date and time of
equinoxes and solstices on Earth[1][2]
event equinox solstice equinox solstice
month March June September December
yeardaytimedaytimedaytimedaytime
2016 2004:312022:352214:212110:45
2017 2010:292104:252220:022116:29
2018 2016:152110:072301:542122:22
2019 2021:582115:542307:502204:19
2020 2003:502021:432213:312110:03
2021 2009:372103:322219:212115:59
2022 2015:332109:142301:042121:48
2023 2021:252114:582306:502203:28
2024 2003:072020:512212:442109:20
2025 2009:022102:422218:202115:03
2026 2014:462108:252300:062120:50
The Earth during the summer solstice in June 2017

The summer solstice occurs during summer.[3] This is the June solstice in the Northern Hemisphere and the December solstice in the Southern Hemisphere. Depending on the shift of the calendar, the summer solstice occurs sometime between June 20 and June 22 in the Northern Hemisphere[4][5] and between December 20 and December 23 in the Southern Hemisphere.[6] The same dates in the opposite hemisphere are referred to as the winter solstice.

Since prehistory, the summer solstice has been seen as a significant time of year in many cultures, and has been marked by festivals and rituals. Traditionally, in many temperate regions (especially Europe), the summer solstice is seen as the middle of summer and referred to as "midsummer". Today, however, in some countries and calendars it is seen as the beginning of summer.

Distinctions

Diagram of the 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.[7] This is because the Earth orbits the Sun in an ellipse, and its orbital speed varies slightly during the year.[8]

Although the Sun appears at its highest altitude from the viewpoint of an observer in outer space or a terrestrial observer outside tropical latitudes, the highest altitude occurs on a different day for certain locations in the tropics, specifically those where the Sun is directly overhead (maximum 90 degrees elevation) at the subsolar point. This day occurs twice each year for all locations between the Tropic of Cancer and Tropic of Capricorn because the overhead Sun appears to cross a given latitude once before the day of the solstice and once afterward. For example, Lahaina Noon occurs in May and July in Hawaii. See solstice article. For all observers, the apparent position of the noon Sun is at its most northerly point on the June solstice and most southerly on the December solstice.

Full moon

2016 was the first time in nearly 70 years that a full moon and the Northern Hemisphere's summer solstice occurred on the same day.[9] The 2016 summer solstice's full moon rose just as the Sun set.[10]

Cultural aspects

The significance given to the summer solstice has varied among cultures, but most recognize the event in some way with holidays, festivals, and rituals around that time with themes of religion or fertility.[11] For example, in Sweden, midsummer is one of the year's major holidays when the country closes down as much as during Christmas. In some regions, the summer solstice is seen as the beginning of summer and the end of spring. In other cultural conventions, the solstice is closer to the middle of summer.[12]

Summer solstice sunset over the Mojave Desert 7:54 p.m. PDT (19:54) June 20, 2016
Longreach, Queensland at mid-day of summer solstice 2019. The town is on the Tropic of Capricorn (Shadow directly below the sign)

Solstice is derived from the Latin words sol (Sun) and sistere (to stand still).

Date

Date of the northern hemisphere's summer solstice over time. The ~25 drops per century are leap years when the date shifts back one day due to the insertion of February 29. There was no leap year in 1800 or 1900, which explains why there is no drop those years.

Celebrations

Winter solstice in the Southern Hemisphere

Length of the day on the summer solstice of the north

The following tables contain information on the length of the day on the 20th June, close to the summer solstice of the Northern Hemisphere and winter solstice of the Southern Hemisphere (i.e. June solstice). The data was collected from the website of the Finnish Meteorological Institute on 20 June 2016[13] as well as from certain other websites.[14][15][16][17][18][19][20][21][22][23]

The data is arranged geographically and within the tables from the longest day to the shortest one.

Fennoscandia and the Baltic states
City Sunrise
20 June 2016
Sunset
20 June 2016
Length of the day
Murmansk24 h
Bodø24 h
Rovaniemi24 h
Luleå1:0021.6.2016 0:0523 h 04 min
Kem’1:4423:4221 h 58 min
Reykjavík2:5521.6.2016 0:0321 h 08 min
Trondheim3:0223:3720 h 35 min
Tórshavn3:3623:2119 h 45 min
Petrozavodsk2:5522:3319 h 38 min
Helsinki3:5422:4918 h 55 min
Saint Petersburg3:3522:2518 h 50 min
Oslo3:5322:4318 h 49 min
Tallinn4:0322:4218 h 39 min
Stockholm3:3022:0718 h 37 min
Riga4:2922:2117 h 52 min
Copenhagen4:2521:5717 h 32 min
Vilnius4:4121:5917 h 17 min
Europe
City Sunrise
20 June 2016
Sunset
20 June 2016
Length of the day
Edinburgh4:2622:0217 h 36 min
Moscow3:4421:1717 h 33 min
Berlin4:4321:3316 h 49 min
Warsaw4:1421:0016 h 46 min
London4:4321:2116 h 38 min
Kyiv4:4621:1216 h 26 min
Paris5:4621:5716 h 10 min
Vienna4:5320:5816 h 04 min
Budapest4:4620:4415 h 58 min
Zürich5:2921:2515 h 56 min
Rome5:3420:4815 h 13 min
Madrid6:4421:4815 h 03 min
Lisbon6:1121:0414 h 52 min
Athens6:0220:5014 h 48 min
Africa
City Sunrise
20 June 2016
Sunset
20 June 2016
Length of the day
Cairo4:5418:5914 h 04 min
Tenerife7:0821:0513 h 57 min
Dakar6:4119:4112 h 59 min
Addis Ababa6:0718:4612 h 38 min
Nairobi6:3218:3512 h 02 min
Kinshasa6:0417:5611 h 52 min
Dar es Salaam6:3218:1611 h 43 min
Luanda6:2017:5611 h 36 min
Jamestown6:4917:5911 h 10 min
Antananarivo6:2117:2110 h 59 min
Windhoek6:3017:1510 h 44 min
Johannesburg6:5417:2410 h 29 min
Cape Town7:5117:449 h 53 min
Middle East
City Sunrise
20 June 2016
Sunset
20 June 2016
Length of the day
Tehran5:4820:2314 h 34 min
Beirut5:2719:5214 h 24 min
Baghdad4:5319:1414 h 21 min
Jerusalem5:3319:4714 h 13 min
Manama4:4518:3213 h 46 min
Doha4:4418:2613 h 42 min
Dubai5:2919:1113 h 42 min
Riyadh5:0418:4413 h 39 min
Muscat5:1918:5513 h 35 min
Sana'a5:3318:3513 h 02 min
Americas
City Sunrise
20 June 2016
Sunset
20 June 2016
Length of the day
Inuvik24 h
Fairbanks2:5721.6. 00:4721 h 49 min
Nuuk2:5321.6. 00:0321 h 09 min
Iqaluit2:1123:0020 h 49 min
Anchorage4:2023:4119 h 21 min
Kodiak5:0723:1418 h 06 min
Sitka4:0622:0017 h 54 min
Unalaska6:3423:4117 h 06 min
Edmonton5:0422:0717 h 02 min
Vancouver5:0621:2116 h 14 min
Seattle5:1121:1015 h 59 min
Ottawa5:1420:5415 h 40 min
Toronto5:3521:0215 h 26 min
New York5:2420:3015 h 05 min
Washington, D.C.5:4220:3614 h 53 min
Los Angeles5:4220:0714 h 25 min
Miami6:3020:1413 h 44 min
Havana6:4420:1713 h 33 min
Honolulu5:5019:1613 h 25 min
Mexico City6:5920:1713 h 18 min
Managua5:2118:1112 h 50 min
Bogotá5:4618:0912 h 23 min
Quito6:1218:1912 h 06 min
Lima6:2717:5211 h 24 min
La Paz6:5918:0811 h 08 min
Rio de Janeiro6:3217:1610 h 43 min
São Paulo6:4717:2810 h 40 min
Porto Alegre7:2017:3210 h 12 min
Santiago7:4617:429 h 56 min
Buenos Aires8:0017:509 h 49 min
Ushuaia9:5817:117 h 12 min
Asia and Oceania
City Sunrise
20 June 2016
Sunset
20 June 2016
Length of the day
Provideniya0:5222:1621 h 23 min
Magadan3:3722:1918 h 41 min
Petropavlovsk4:5821:5516 h 56 min
Khabarovsk4:5721:0416 h 07 min
Ulaanbaatar5:5221:5416 h 01 min
Vladivostok5:3220:5515 h 22 min
Beijing4:4519:4615 h 00 min
Seoul5:1119:5614 h 46 min
Tokyo4:2519:0014 h 34 min
Shanghai4:5019:0114 h 10 min
Lhasa6:5520:5814 h 03 min
Delhi5:2319:2113 h 58 min
Kathmandu5:0819:0213 h 53 min
Taipei5:0418:4613 h 41 min
Hong Kong5:3919:0913 h 30 min
Manila5:2718:2712 h 59 min
Bangkok5:5118:4712 h 56 min
Singapore7:0019:1212 h 11 min
Jakarta6:0117:4711 h 45 min
Darwin7:0618:2911 h 23 min
Papeete6:2717:3211 h 04 min
Sydney6:5916:539 h 53 min
Auckland7:3317:119 h 37 min
Melbourne7:3517:079 h 32 min
Dunedin8:1916:598 h 39 min

Length of day increases from the equator towards the North Pole in the Northern Hemisphere in June (around the summer solstice there), but decreases towards the South Pole in the Southern Hemisphere at the time of the southern winter solstice.

See also

References

  1. United States Naval Observatory (January 4, 2018). "Earth's Seasons and Apsides: Equinoxes, Solstices, Perihelion, and Aphelion". Archived from the original on 24 Dec 2017. Retrieved September 18, 2018.
  2. "Solstices and Equinoxes: 2001 to 2100". AstroPixels.com. February 20, 2018. Retrieved December 21, 2018.
  3. "When does spring start?". Archived from the original on 2016-11-25. Retrieved 2016-11-12.
  4. "The June Solstice". Time and Date AS. Archived from the original on 2012-02-04. Retrieved 2012-01-30.
  5. "Solstice (astronomy)". Britannica Online Encyclopedia. Archived from the original on 2011-06-25. Retrieved 2011-06-20.
  6. "December Solstice". Time and Date AS. Archived from the original on 2012-01-18. Retrieved 2012-01-30.
  7. "US Naval Observatory: Sunrise and Sunset Times Near the Solstices". Archived from the original on 18 June 2017. Retrieved 21 June 2017.
  8. "The Long Story (USNO explanation)". Archived from the original on 18 June 2017. Retrieved 21 June 2017.
  9. "Full Moon and Winter Solstice coincide on the same day". The Old Farmer's Almanac. Archived from the original on 23 June 2016. Retrieved 21 June 2016.
  10. "Full Moon and Summer Solstice coincide on the same day". The Old Farmer's Almanac. Archived from the original on 22 June 2016. Retrieved 21 June 2016.
  11. "Summer solstice celebrations of Christianity, Judaism, Neopaganism, etc". Religioustolerance.org. Archived from the original on 2011-06-28. Retrieved 2011-06-20.
  12. "The Astronomical vs. Meteorological Seasons". Archived from the original on 2016-11-14. Retrieved 2016-11-13.
  13. "Paikallissää Helsinki" [‘Local weather in Helsinki’] (in Finnish). Finnish Meteorological Institute. 2016-06-20. Retrieved 2016-06-20.
  14. "Jamestown, Saint Helena". Retrieved 2016-06-22.
  15. "Fairbanks". Retrieved 2016-06-22.
  16. "Nuuk". Retrieved 2016-06-22.
  17. "Iqaluit". Retrieved 2016-06-22.
  18. "Sitka". Retrieved 2016-06-22.
  19. "Unalaska". Retrieved 2016-06-22.
  20. "Provideniya". Retrieved 2016-06-22.
  21. "Katmandu". Retrieved 2016-06-22.
  22. "Edmonton, Canada". Retrieved 2016-06-22.
  23. "Inuvik, Canada". Retrieved 2020-12-19.
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