Winter solstice

This article is about the astronomical phenomenon. For other uses, see Winter solstice (disambiguation).

"Midwinter" redirects here. For other uses, see Midwinter (disambiguation).

Winter solstice
Lawrence Hall of Science visitors observe sunset on the day of the winter solstice using the Sunstones II.
Also called	Midwinter, Yule, the Longest Night, Jól
Observed by	Various cultures
Type	Cultural, seasonal, astronomical
Significance	Astronomically marks the beginning of shortening nights and lengthening days
Celebrations	Festivals, spending time with loved ones, feasting, singing, dancing, fires
Date	Between December 21 and December 23 (NH) Between June 20 and June 21 (SH)
Frequency	Twice a year (once in the northern hemisphere, once in the southern hemisphere, six months apart)
Related to	Winter festivals and the solstice

Winter solstice in Northern Hemisphere over Asia

Winter solstice is an astronomical phenomenon marking the shortest day and the longest night of the year. In the Northern Hemisphere this is the December solstice and in the Southern Hemisphere this is the June solstice.

The axial tilt of Earth and gyroscopic effects of its daily rotation mean that the two opposite points in the sky to which the Earth's axis of rotation points (axial precession) change very slowly (making a complete circle approximately every 26,000 years). As the Earth follows its orbit around the Sun, the polar hemisphere that faced away from the Sun, experiencing winter, will, in half a year, face towards the Sun and experience summer. This is because the two hemispheres face opposite directions along Earth's axis, and so as one polar hemisphere experiences winter, the other experiences summer.

More evident from high latitudes, a hemisphere's winter solstice occurs on the shortest day and longest night of the year, when the sun's daily maximum elevation in the sky is at its lowest. The winter solstice itself lasts only a moment in time, so other terms are used for the day on which it occurs, such as "midwinter", or the "shortest day". It is often considered the "extreme of winter" (Dongzhi in the Chinese calendar). In meteorology, winter in the Northern Hemisphere spans the entire period of December through February. The seasonal significance of the winter solstice is in the reversal of the gradual lengthening of nights and shortening of days. The earliest sunset and latest sunrise dates differ from winter solstice, however, and these depend on latitude, due to the variation in the solar day throughout the year caused by the Earth's elliptical orbit (see earliest and latest sunrise and sunset).

Worldwide, interpretation of the event has varied across cultures, but many have held a recognition of rebirth, involving holidays, festivals, gatherings, rituals or other celebrations around that time.

History and cultural significance

Japanese Sun goddess Amaterasu emerging from a cave

The solstice may have been a special moment of the annual cycle for some cultures even during neolithic times. Astronomical events were often used to guide activities such as the mating of animals, the sowing of crops and the monitoring of winter reserves of food. Many cultural mythologies and traditions are derived from this. This is attested by physical remains in the layouts of late Neolithic and Bronze Age archaeological sites, such as Stonehenge in England and Newgrange in Ireland. The primary axes of both of these monuments seem to have been carefully aligned on a sight-line pointing to the winter solstice sunrise (Newgrange) and the winter solstice sunset (Stonehenge). It is significant that at Stonehenge the Great Trilithon was erected outwards from the centre of the monument, i.e. its smooth flat face was turned towards the midwinter Sun. The winter solstice was immensely important because the people were economically dependent on monitoring the progress of the seasons. Starvation was common during the first months of the winter, January to April (northern hemisphere) or July to October (southern hemisphere), also known as "the famine months". In temperate climates, the midwinter festival was the last feast celebration, before deep winter began. Most cattle were slaughtered so they would not have to be fed during the winter, so it was almost the only time of year when a plentiful supply of fresh meat was available. The majority of wine and beer made during the year was finally fermented and ready for drinking at this time. The concentration of the observances were not always on the day commencing at midnight or at dawn, but at the beginning of the pagan day, which in many cultures fell on the previous eve. Because the event was seen as the reversal of the Sun's ebbing presence in the sky, concepts of the birth or rebirth of sun gods have been common and, in cultures which used cyclic calendars based on the winter solstice, the "year as reborn" was celebrated with reference to life-death-rebirth deities or "new beginnings" such as Hogmanay's redding, a New Year cleaning tradition. Also "reversal" is yet another frequent theme, as in Saturnalia's slave and master reversals.

The pagan Scandinavian and Germanic people of northern Europe celebrated a twelve-day "midwinter" (winter solstice) holiday called Yule (also called Jul, Julblot, jólablót, midvinterblot, julofferfest). Many modern Christmas traditions, such as the Christmas tree, the Christmas wreath, the Yule log, and others, are direct descendents of Yule customs. Scandinavians still call Yule "Jul". In English, the word "Yule" is often used in combination with the season "yuletide" a usage first recorded in 900. It is believed that the celebration of this day was a worship of these peculiar days, interpreted as the reawakening of nature. The Yule (Jul) particular god was Jólner, which is one of Odin's many names. The concept of Yule occurs in a tribute poem to Harold Hårfager from about AD 900, where someone said "drinking Jul". Julblot is the most solemn sacrifice feast. At the "julblotet", sacrifices were given to the gods to earn blessing on the forthcoming germinating crops. Julblotet was eventually integrated into the Christian Christmas. As a remainder from this Viking era, the Midsummer is still important in Scandinavia, and hence vividly celebrated.

Sol Invictus ("The Unconquered Sun") was originally a Syrian god who was later adopted as the chief god of the Roman Empire under Emperor Aurelian. His holiday is traditionally celebrated on December 25, as are several gods associated with the winter solstice in many pagan traditions.

The Christmas carol In The Bleak Midwinter refers to the Winter solstice in its title.

Observances

Main article: List of multinational festivals and holidays

Although the instant of the solstice can be calculated, direct observation of the solstice by amateurs is impossible because the sun moves too slowly or appears to stand still (the meaning of "solstice"). However, by use of astronomical data tracking, the precise timing of its occurrence is now public knowledge. One cannot directly detect the precise instant of the solstice (by definition, one cannot observe that an object has stopped moving until one later observes that it has not moved further from the preceding spot, or that it has moved in the opposite direction). Further, to be precise to a single day, one must be able to observe a change in azimuth or elevation less than or equal to about 1/60 of the angular diameter of the sun. Observing that it occurred within a two-day period is easier, requiring an observation precision of only about 1/16 of the angular diameter of the sun. Thus, many observations are of the day of the solstice rather than the instant. This is often done by observing the sunrise and sunset or using an astronomically aligned instrument that allows a ray of light to be cast on a certain point around that time. Before the scientific revolution, many forms of observances, astronomical, symbolic or ritualistic, had evolved according to the beliefs of various cultures, many of which are still practiced today.

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  Neolithic site of Goseck circle. The yellow lines are the direction the Sun rises and sets at winter solstice.

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  Sunrise at Stonehenge on the Winter Solstice

Holidays celebrated on the winter solstice

• Blue Christmas (holiday)
• Brumalia (Ancient Rome)
• Dongzhi Festival (Asia)
• Global Orgasm
• Korochun (Slavic)
• Midsummer in the Southern Hemisphere. (Neopagan)
• Sanghamitta Day (Theravada Buddhism)
• Shalako (Zuni)
• Yaldā (Iran)
• Yule in the Northern Hemisphere (Neopagan)
• Ziemassvētki (ancient Latvia)

The length of the day on the winter solstice of the north

The following tables contain information on the length of the day on the winter solstice of the northern hemisphere. The data was collected from the website of the Finnish Meteorological Institute on 22 December 2015. The data is arranged geographically and within the tables from the shortest day to the longest one.

Skandinavia and the Baltic states
City	Sunrise 22 Dec 2015	Sunset 22 Dec 2015	Length of the day
Rovaniemi	11:08	13:24	2 h 16 min
Reykjavik	11:22	15:30	4 h 08 min
Trondheim	10:02	14:33	4 h 31 min
Tórshavn	9:51	15:00	5 h 09 min
Helsinki	9:25	15:14	5 h 49 min
Oslo	9:19	15:13	5 h 54 min
Tallinn	9:18	15:21	6 h 03 min
Stockholm	8:44	14:49	6 h 05 min
Riga	9:01	15:44	6 h 43 min
Copenhagen	8:38	15:39	7 h 01 min
Vilnius	8:41	15:55	7 h 14 min

Europe
City	Sunrise 22 Dec 2015	Sunset 22 Dec 2015	Length of the day
Edinburgh	8:42	15:40	6 h 58 min
Moscow	8:58	15:59	7 h 01 min
Berlin	8:15	15:54	7 h 39 min
London	8:04	15:54	7 h 50 min
Kiev	7:56	15:56	8 h 00 min
Paris	8:42	16:56	8 h 14 min
Rome	7:35	16:42	9 h 07 min
Madrid	8:35	17:52	9 h 17 min
Lisboa	7:51	17:19	9 h 28 min
Athens	7:38	17:09	9 h 31 min

Africa
City	Sunrise 22 Dec 2015	Sunset 22 Dec 2015	Length of the day
Cairo	6:47	17:00	10 h 13 min
Dakar	7:30	18:46	11 h 16 min
Addis Abeba	6:36	18:12	11 h 36 min
Kinshasa	5:46	18:08	12 h 22 min
Dar es Salaam	6:06	18:37	12 h 31 min
Luanda	5:46	18:25	12 h 39 min
Windhoek	6:04	19:36	13 h 32 min
Johannesburg	5:13	19:00	13 h 47 min
Cape Town	5:32	19:57	14 h 25 min

Americas
City	Sunrise 22 Dec 2015	Sunset 22 Dec 2015	Length of the day
Anchorage	10:15	15:42	5 h 27 min
Vancouver	8:05	16:17	8 h 12 min
Seattle	7:55	16:21	8 h 26 min
Ottawa	7:40	16:23	8 h 43 min
New York	7:17	16:32	9 h 15 min
Washington, D.C.	7:23	16:50	9 h 27 min
Los Angeles	6:55	16:48	9 h 53 min
Miami	7:03	17:35	10 h 32 min
Honolulu	7:05	17:55	10 h 50 min
México City	7:06	18:04	10 h 58 min
Managua	6:01	17:26	11 h 25 min
Bogotá	5:59	17:51	11 h 52 min
Quito	6:08	18:17	12 h 09 min
Lima	5:42	18:32	12 h 50 min
Rio de Janeiro	6:05	19:38	13 h 33 min
Santiago de Chile	6:30	20:52	14 h 22 min
Buenos Aires	5:38	20:06	14 h 28 min
Ushuaia	4:52	22:12	17 h 20 min

Asia and Oceania
City	Sunrise 22 Dec 2015	Sunset 22 Dec 2015	Length of the day
Magadan	10:55	16:56	6 h 01 min
Petropavlovsk	9:37	17:11	7 h 34 min
Khabarovsk	9:49	18:07	8 h 18 min
Ulan Bator	8:40	17:03	8 h 23 min
Vladivostok	9:41	18:41	9 h 00 min
Peking	7:33	16:53	9 h 20 min
Tokyo	6:48	16:32	9 h 44 min
Shanghai	6:49	16:57	10 h 08 min
Lhasa	8:47	19:02	10 h 15 min
Delhi	7:10	17:29	10 h 19 min
Hong Kong	6:59	17:45	10 h 46 min
Manila	6:17	17:33	11 h 16 min
Bangkok	6:37	17:56	11 h 19 min
Singapore	7:02	19:05	12 h 03 min
Jakarta	5:37	18:06	12 h 29 min
Darwin	6:20	19:11	12 h 51 min
Papeete	5:22	18:33	13 h 11 min
Sydney	5:42	20:06	14 h 24 min
Auckland	5:58	20:40	14 h 42 min
Melbourne	5:55	20:43	14 h 48 min
Dunedin	5:44	21:28	15 h 44 min

See also

• Burning the Clocks
• Christmas in July
• December solstice
• Effect of sun angle on climate
• Festival of Lights (disambiguation)
• Festive ecology
• Festivus
• Halcyon days
• Hanukkah
• HumanLight
• June solstice
• Koliada
• Kwanzaa
• Lohri
• Midsummer
• Summer solstice
• Thai Pongal
• Tiregān

External links

• Table of times/dates from 1600-2400