December 21
December 21 is the 356th day of the year in the Gregorian calendar; 10 days remain until the year's end. It falls in winter (northern hemisphere) and under the astrological sign of Sagittarius.
External references
Curated jump-off points to the major almanacs, encyclopaedias and primary sources for this date.
Astronomy
On December 21 the Sun's declination is approximately -23.4°. At this latitude the Sun is south of the celestial equator, giving the Northern Hemisphere shorter days than nights.
For specific rise/set times at your location, see the U.S. Naval Observatory, or the NASA APOD archive for any imagery published on a December 21.
Position in the year
Holidays & observances
- Armed Forces Day (Philippines)
- Christian feast day: O Oriens
- Christian feast day: Peter Canisius
- Christian feast day: Thomas the Apostle
- Christian feast day: December 21 (Eastern Orthodox liturgics)
Events
A selection of widely-documented historical events that took place on this date. Years marked BCE follow standard astronomical convention.
2023 — Fourteen people are killed and 25 others injured during a mass shooting at Charles University in Prague, Czech Republic. ↗(3 years ago)more
On 21 December 2023, a mass shooting occurred at Charles University's Faculty of Arts main building in central Prague, Czech Republic. A lone gunman, 24-year-old postgraduate student David Kozák, killed 13 people and injured 25 others before committing suicide after exchanging gunfire with police; an additional victim died indirectly from falling to her d...
2020 — A great conjunction of Jupiter and Saturn occurs, with the two planets separated in the sky by 0.1 degrees. This is the closest conjunction between the two planets since 1623. ↗(6 years ago)more
A great conjunction is a conjunction of the planets Jupiter and Saturn, when the two planets appear closest together in the sky. Great conjunctions occur approximately every 20 years when Jupiter "overtakes" Saturn in its orbit. They are named "great" for being by far the rarest of the conjunctions between naked-eye planets.
2012 — 2012 phenomenon: Festivities are held in parts of Mesoamerica to commemorate the conclusion of b'ak'tun 13, a roughly 5,126-year-long cycle in the Mesoamerican Long Count Calendar whose passing many New Age spiritualists had earlier held to portend a variety of cataclysmic or transformative events. ↗(14 years ago)more
The 2012 phenomenon was a range of eschatological beliefs that cataclysmic or transformative events would occur on or around 21 December 2012. This date was regarded as the end-date of a 5,126-year-long cycle in the Mesoamerican Long Count calendar, and festivities took place on 21 December 2012 to commemorate the event in the countries that were part of ...
2004 — Iraq War: A suicide bomber kills 22 at the forward operating base next to the main U.S. military airfield at Mosul, Iraq, the single deadliest suicide attack on American soldiers in Iraq. ↗(22 years ago)more
The Iraq War, also referred to as the Second Gulf War, was a protracted armed conflict in Iraq from 2003 to 2011. It began with the invasion by a United States–led coalition, which resulted in the overthrow of the Ba'athist government of Saddam Hussein.
1999 — The Spanish Civil Guard intercepts a van loaded with 950 kg of explosives that ETA intended to use to blow up Torre Picasso in Madrid, Spain. ↗(27 years ago)more
The Civil Guard is one of the two national law enforcement agencies of Spain. As a national gendarmerie, it is military in nature and is responsible for civil policing under the authority of both the Ministry of the Interior and the Ministry of Defence.
1999 — Cubana de Aviación Flight 1216 overshoots the runway at La Aurora International Airport, killing 18. ↗(27 years ago)more
Cubana de Aviación Flight 1216 was a McDonnell Douglas DC-10 that overran the runway at La Aurora International Airport, Guatemala City, on 21 December 1999. 8 passengers and 8 crew members on board were killed as well as 2 people on the ground.
1995 — The city of Bethlehem passes from Israeli to Palestinian control. ↗(31 years ago)more
Bethlehem is a city in the West Bank, Palestine, located about ten kilometres south of Jerusalem, and the capital of the Bethlehem Governorate. It had a population of 28,591 people, as of 2017. The city's economy is strongly linked to tourism, especially during the Christmas period, when Christians embark on a pilgrimage to the Church of the Nativity, whi...
1992 — A Dutch DC-10, flight Martinair MP 495, crashes at Faro Airport, Portugal, killing 56. ↗(34 years ago)more
The Netherlands, informally Holland, is a country in Northwestern Europe, with overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Netherlands. The Netherlands consists of twelve provinces and three overseas special municipalities.
1991 — Dissolution of the Soviet Union: The leaders of 11 now effectively autonomous Soviet republics sign the Alma-Ata Protocol establishing the Commonwealth of Independent States in place of the collapsing Soviet Union. ↗(35 years ago)more
The Soviet Union was formally dissolved as a sovereign state and subject of international law on 26 December 1991 by Declaration No. 142-N of the Soviet of the Republics of the Supreme Soviet of the Soviet Union.
1988 — A bomb explodes on board Pan Am Flight 103 over Lockerbie, Dumfries and Galloway, Scotland, killing 270. This is to date the deadliest air disaster to occur on British soil. ↗(38 years ago)more
Pan Am Flight 103 was a regularly scheduled Pan Am transatlantic flight from Frankfurt to Detroit via a stopover in London and another in New York City. Shortly after 19:00 on 21 December 1988, the Boeing 747 Clipper Maid of the Seas was destroyed by a bomb while flying over the Scottish town of Lockerbie, killing all 243 passengers and 16 crew aboard.
1979 — Lancaster House Agreement: An independence agreement for Rhodesia is signed in London by Lord Carrington, Sir Ian Gilmour, Robert Mugabe, Joshua Nkomo, Bishop Abel Muzorewa and S.C. Mundawarara. ↗(47 years ago)more
The Lancaster House Agreement is an agreement signed on 21 December 1979 in Lancaster House, following the conclusion of a constitutional conference where different parties discussed the future of Zimbabwe Rhodesia, formerly known as Rhodesia. The agreement effectively concluded the Rhodesian Bush War.
- 1973 — The Geneva Conference on the Arab–Israeli conflict opens. ↗(53 years ago)
more
The Geneva Conference of 1973 was an attempt to negotiate a solution to the Arab–Israeli conflict as envisioned in United Nations Security Council Resolution 338 following the called-for cease-fire to end the Yom Kippur War.
Notable births
2006 — Cooper Flagg, American basketball player ↗(20 years ago)more
Cooper Flagg is an American professional basketball player for the Dallas Mavericks of the National Basketball Association (NBA). He was the first overall pick of the 2025 NBA draft, selected by the Mavericks, and became that season's Rookie of the Year.
2002 — Clara Tauson, Danish tennis player ↗(24 years ago)more
Clara Tauson is a Danish professional tennis player. Her career-high rankings are world No. 12 in singles on 8 September 2025 and No. 65 in doubles on 16 February 2025. Tauson has won three WTA Tour titles, all on hardcourts.
1997 — Madelyn Cline, American actress and model ↗(29 years ago)more
Madelyn Cline is an American actress and model. She is best known for her roles in the Netflix teen drama series Outer Banks (2020–present), in Rian Johnson's mystery film Glass Onion: A Knives Out Mystery (2022), and in the slasher film I Know What You Did Last Summer (2025).
1997 — Charlie McAvoy, American ice hockey player ↗(29 years ago)more
Charles Patrick McAvoy Jr. is an American professional ice hockey player who is a defenseman and alternate captain for the Boston Bruins of the National Hockey League (NHL). He was selected 14th overall in the 2016 NHL entry draft.
1996 — Ben Chilwell, English footballer ↗(30 years ago)more
Benjamin James Chilwell is an English professional footballer who plays as a left-back or left wing-back forLigue 1 club Strasbourg.
1996 — Kaitlyn Dever, American actress ↗(30 years ago)more
Kaitlyn Rochelle Dever is an American actress. She is best known for her roles in the television series Justified (2011–2015), Last Man Standing (2011–2021), Unbelievable (2019), Dopesick (2021), Apple Cider Vinegar (2025), and The Last of Us (2025–present).
Notable deaths
2024 — Michelle Botes, South African actress (born 1962) ↗(2 years ago)more
Michélle Botes was a South African actress, language instructor, designer and aromatherapist. She is best known for her roles in the television soapies Legacy (2020), Isidingo (1998) and Arende (1994).
2024 — Art Evans, American actor (born 1942) ↗(2 years ago)more
Arthur James Evans was an American actor who made multiple film and television appearances over five decades.
2019 — Andrew Clennel Palmer, British engineer (born 1938) ↗(7 years ago)more
Andrew Clennel Palmer was a British engineer who worked on offshore geotechnical problems of submarine pipeline design and the study of the properties of ice. He spent much of his career as a teacher and academic researcher, at the University of Liverpool, Cambridge University, the University of Manchester Institute of Science and Technology, and the Nati...
2017 — Bruce McCandless II, US astronaut who conducted the first untethered spacewalk (born 1937) ↗(9 years ago)more
Bruce McCandless II was an American Navy officer and aviator, electrical engineer, and NASA astronaut. In 1984, during the first of his two Space Shuttle missions, he completed the first untethered spacewalk by using the Manned Maneuvering Unit.
2014 — Udo Jürgens, Austrian-Swiss singer-songwriter and pianist (born 1934) ↗(12 years ago)more
Udo Jürgens was an Austrian composer and singer of popular music whose career spanned over 50 years. He won the Eurovision Song Contest 1966 for Austria, composed close to 1,000 songs, and sold over 104 million records. In 2007, he additionally obtained Swiss citizenship.
Numerical & calendrical curiosities
| Day-of-year (356) | 2^2 × 89 · composite (no) |
|---|---|
| Days remaining (10) | 2 × 5 |
| Date code DDMMYYYY | 21122026 · next palindrome year: 2112 |
| Sun declination | -23.43° (Cooper approximation) |
| Distance from solstice | 1 days |