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 or 21 June) and in the Southern Hemisphere, this is the December solstice (21 or 22 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°.

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]

Culture

There is evidence that the summer solstice has been culturally important since the Neolithic era. Many ancient monuments in Europe especially, as well as parts of the Middle East, Asia and the Americas, are aligned with the sunrise or sunset on the summer solstice (see archaeoastronomy).^[9][10] The significance of 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 fertility.^[11] In the Roman Empire, the traditional date of the summer solstice was 24 June.^[12] In Germanic-speaking cultures, the time around the summer solstice is called 'midsummer'. Traditionally in northern Europe midsummer was reckoned as the night of 23–24 June, with summer beginning on May Day.^[13] The summer solstice continues to be seen as the middle of summer in many European cultures, but in some cultures or calendars it is seen as summer's beginning.^[14] In Sweden, midsummer is one of the year's major holidays when the country closes down as much as during Christmas.

Observances

Traditional festivals

• Saint John's Eve (Europe), including:
  • Jaanipäev (Estonia)
  • Jāņi (Latvia)
  • Joninės (Lithuania)
  • Jónsmessa (Iceland)
  • Golowan (Cornwall)
• Kupala Night (Slavic peoples)
• Yhyakh (Yakuts)
• Tiregān (Iran)
• Xiazhi (China)

Modern observances

• National Indigenous Peoples Day (Canada)
• Day of Private Reflection (Northern Ireland)
• Fremont Solstice Parade (Fremont, Seattle, Washington, United States)
• Santa Barbara Summer Solstice Parade (Santa Barbara, California, United States)
• International Yoga Day
• Fête de la Musique, also known as World Music Day

Length of the day on northern summer solstice

The following tables contain information on the length of the day on 20 June 2016, close to the summer solstice of the Northern Hemisphere and winter solstice of the Southern Hemisphere. The data was collected from the website of the Finnish Meteorological Institute^[15] as well as from certain other websites.^{[16][17][18][19][20][21][22][23][24][25][26]}

The data is arranged geographically and within the tables from the longest day to the shortest one. Times that occur the next day (21 June) are marked with ⁺.

Fennoscandia and the Baltic states
City	Sunrise 20 June 2016	Sunset 20 June 2016	Length of the day
Murmansk	—	—	24 h
Apatity	—	—	24 h
Bodø	—	—	24 h
Rovaniemi	—	—	24 h
Luleå	1:00	0:05+	23 h 04 min
Arkhangelsk	1:34	23:04	21 h 30 min
Reykjavík	2:55	0:03+	21 h 08 min
Trondheim	3:02	23:37	20 h 35 min
Tórshavn	3:36	23:21	19 h 45 min
Petrozavodsk	2:55	22:33	19 h 38 min
Helsinki	3:54	22:49	18 h 55 min
Saint Petersburg	3:35	22:25	18 h 50 min
Oslo	3:53	22:43	18 h 49 min
Tallinn	4:03	22:42	18 h 39 min
Stockholm	3:30	22:07	18 h 37 min
Riga	4:29	22:21	17 h 52 min
Copenhagen	4:25	21:57	17 h 32 min
Vilnius	4:41	21:59	17 h 17 min

Europe
City	Sunrise 20 June 2016	Sunset 20 June 2016	Length of the day
Edinburgh	4:26	22:02	17 h 36 min
Moscow	3:44	21:17	17 h 33 min
Berlin	4:43	21:33	16 h 49 min
Warsaw	4:14	21:00	16 h 46 min
London	4:43	21:21	16 h 38 min
Kyiv	4:46	21:12	16 h 26 min
Paris	5:46	21:57	16 h 10 min
Vienna	4:53	20:58	16 h 04 min
Budapest	4:46	20:44	15 h 58 min
Zürich	5:29	21:25	15 h 56 min
Rome	5:34	20:48	15 h 13 min
Madrid	6:44	21:48	15 h 03 min
Lisbon	6:11	21:04	14 h 52 min
Athens	6:02	20:50	14 h 48 min

Africa
City	Sunrise 20 June 2016	Sunset 20 June 2016	Length of the day
Cairo	4:54	18:59	14 h 04 min
Tenerife	7:08	21:05	13 h 57 min
Dakar	6:41	19:41	12 h 59 min
Addis Ababa	6:07	18:46	12 h 38 min
Nairobi	6:32	18:35	12 h 02 min
Kinshasa	6:04	17:56	11 h 52 min
Dar es Salaam	6:32	18:16	11 h 43 min
Luanda	6:20	17:56	11 h 36 min
Jamestown	6:49	17:59	11 h 10 min
Antananarivo	6:21	17:21	10 h 59 min
Windhoek	6:30	17:15	10 h 44 min
Johannesburg	6:54	17:24	10 h 29 min
Cape Town	7:51	17:44	9 h 53 min

Middle East
City	Sunrise 20 June 2016	Sunset 20 June 2016	Length of the day
Tehran	5:48	20:23	14 h 34 min
Beirut	5:27	19:52	14 h 24 min
Baghdad	4:53	19:14	14 h 21 min
Jerusalem	5:33	19:47	14 h 13 min
Manama	4:45	18:32	13 h 46 min
Doha	4:44	18:26	13 h 42 min
Dubai	5:29	19:11	13 h 42 min
Riyadh	5:04	18:44	13 h 39 min
Muscat	5:19	18:55	13 h 35 min
Sana'a	5:33	18:35	13 h 02 min

Americas
City	Sunrise 20 June 2016	Sunset 20 June 2016	Length of the day
Inuvik	—	—	24 h
Fairbanks	2:57	0:47+	21 h 49 min
Nuuk	2:53	0:03+	21 h 09 min
Iqaluit	2:11	23:00	20 h 49 min
Anchorage	4:20	23:41	19 h 21 min
Kodiak	5:07	23:14	18 h 06 min
Sitka	4:06	22:00	17 h 54 min
Unalaska	6:34	23:41	17 h 06 min
Edmonton	5:04	22:07	17 h 02 min
Winnipeg	5:19	21:40	16 h 21 min
Vancouver	5:06	21:21	16 h 14 min
Seattle	5:11	21:10	15 h 59 min
Ottawa	5:14	20:54	15 h 40 min
Toronto	5:35	21:02	15 h 26 min
New York	5:24	20:30	15 h 05 min
Washington, D.C.	5:42	20:36	14 h 53 min
Los Angeles	5:42	20:07	14 h 25 min
Miami	6:30	20:14	13 h 44 min
Havana	6:44	20:17	13 h 33 min
Honolulu	5:50	19:16	13 h 25 min
Mexico City	6:59	20:17	13 h 18 min
Kingston	5:32	18:45	13 h 13 min
Bridgetown	5:33	18:27	12 h 54 min
Managua	5:21	18:11	12 h 50 min
Port of Spain	5:45	18:30	12 h 45 min
Georgetown	5:38	18:09	12 h 31 min
Bogotá	5:46	18:09	12 h 23 min
Quito	6:12	18:19	12 h 06 min
Lima	6:27	17:52	11 h 24 min
La Paz	6:59	18:08	11 h 08 min
Rio de Janeiro	6:32	17:16	10 h 43 min
São Paulo	6:47	17:28	10 h 40 min
Porto Alegre	7:20	17:32	10 h 12 min
Santiago	7:46	17:42	9 h 56 min
Buenos Aires	8:00	17:50	9 h 49 min
Ushuaia	9:58	17:11	7 h 12 min

Asia and Oceania
City	Sunrise 20 June 2016	Sunset 20 June 2016	Length of the day
Provideniya	0:52	22:16	21 h 23 min
Magadan	3:37	22:19	18 h 41 min
Petropavlovsk	4:58	21:55	16 h 56 min
Khabarovsk	4:57	21:04	16 h 07 min
Ulaanbaatar	5:52	21:54	16 h 01 min
Vladivostok	5:32	20:55	15 h 22 min
Beijing	4:45	19:46	15 h 00 min
Seoul	5:11	19:56	14 h 46 min
Tokyo	4:25	19:00	14 h 34 min
Shanghai	4:50	19:01	14 h 10 min
Lhasa	6:55	20:58	14 h 03 min
Delhi	5:23	19:21	13 h 58 min
Kathmandu	5:08	19:02	13 h 53 min
Taipei	5:04	18:46	13 h 41 min
Hong Kong	5:39	19:09	13 h 30 min
Manila	5:27	18:27	12 h 59 min
Bangkok	5:51	18:47	12 h 56 min
Singapore	7:00	19:12	12 h 11 min
Jakarta	6:01	17:47	11 h 45 min
Darwin	7:06	18:29	11 h 23 min
Papeete	6:27	17:32	11 h 04 min
Sydney	6:59	16:53	9 h 53 min
Auckland	7:33	17:11	9 h 37 min
Melbourne	7:35	17:07	9 h 32 min
Dunedin	8:19	16:59	8 h 39 min

The 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.