March Signals Autumn Equinox for American Samoa and Jarvis Island

Summary: March signals an autumn equinox for American Samoa and Jarvis, the only two U.S. possessions in the Southern Hemisphere.

NASA’s DC-8 flying laboratory’s stop in American Samoa in summer 2016, during first round of Atom (Atmospheric Tomography) flights: NASA photo, Public Domain, via NASA

March signals an autumn equinox for American Samoa and Jarvis, the only two U.S. possessions located in the Southern Hemisphere.

Location north or south of the equator determines the seasonal significance of Earth’s annual pair of equinoxes (Latin: aequus, “equal” + nox, “night”). The March equinox announces spring in the Northern Hemisphere and autumn in the Southern Hemisphere. September’s equinox opens autumn in the Northern Hemisphere and spring in the Southern Hemisphere.

The United States primarily occupies the Northern Hemisphere. Two possessions, however, lie in the Southern Hemisphere. American Samoa and Jarvis Island both occupy the Southern Hemisphere.

American Samoa’s CIA (Central Intelligence Agency) geographic coordinates of 14 degrees 20 minutes south latitude and 170 degrees west longitude situate the unincorporated U.S. territory in the South Pacific Ocean. Swains Island is American Samoa’s northernmost island. The U.S. Department of the Interior gives geographic coordinates of 11 degrees 3 minutes south latitude and 170 degrees 55 minutes west longitude for the privately owned atoll.

American Samoa observes Samoa Standard Time year-round. The 2019 March equinox ushers in astronomical autumn in American Samoa. The unincorporated, South Pacific, U.S. territory experiences the instant of the 2019 autumn equinox Wednesday, March 20, at 10:58 SST.

Jarvis Island’s CIA geographic coordinates of 0 degrees 22 minutes south latitude and 160 degrees 1 minute west longitude situate the unincorporated, unorganized U.S. territory in the South Pacific Ocean. The uninhabited coral island is located almost halfway between Hawaii and New Zealand’s associated state, the self-governing Cook Islands.

The U.S. Central Intelligence Agency’s Map of Standard Time Zones of the World, as of May 2018, places Jarvis Island within the UTC-11 offset, indicating the local time on Jarvis Island lags 11 hours behind Coordinated Universal Time. Jarvis Island observes standard time year-round. As with American Samoa, the 2019 autumn equinox begins Wednesday, March 20, at 10:58 a.m. on Jarvis Island.

The International Organization for Standardization (ISO) is a non-governmental organization, headquartered in Geneva, Switzerland. ISO Code 3166-1 standardizes names of countries and their subdivisions. The ISO assigns the statistical designation of United States Minor Outlying Islands (USMOI) to nine of the 14 U.S. insular areas.

Jarvis Island joins Baker Island, Howland Island, Johnston Atoll, Kingman Reed, Midway Atoll, Navassa Island, Palmyra Atoll and Wake Island as U.S. Minor Outlying Islands. Navassa Island is the only USMOI in the Caribbean Sea. Navassa Island’s CIA geographic coordinates are 18 degrees 25 minutes north latitude and 75 degrees 2 minutes west longitude. The Pacific Ocean claims Jarvis Island and the seven other minor outlying islands.

Except for Jarvis Island, the U.S. Minor Outlying Islands experience the March equinox as a spring equinox. Kingman’s Reef, Midway Atoll and Palmyra Atoll share the same UTC-11 offset with Jarvis Island. They experience the March event as a spring equinox at 10:58 a.m.

Kingman Reef and Palmyra Atoll are located south of Hawaii, in the Northern Line Islands. Kingman Reef’s CIA coordinates are 6 degrees 23 minutes north latitude, 162 degrees 25 minutes west longitude. Palmyra Atoll’s CIA coordinates are 5 degrees 53 minutes north latitude, 162 degrees 5 minutes west longitude.

Johnston Atoll has a UTC-10 offset on the CIA’s May 2018 world time zone map. The 2019 spring equinox takes place at 11:58 a.m. for Johnston Atoll. Johnston Atoll’s CIA coordinates are 16 degrees 45 minutes north latitude, 169 degrees 31 minutes west longitude.

The CIA’s May 2018 world time zone map designates UTC-12 offsets for Baker and Howland Islands. The 2019 spring equinox happens at 9:58 a.m. for both Central Pacific, uninhabited atolls.

Baker Island’s CIA coordinates are 0 degrees 13 minutes north latitude, 176 degrees 28 minutes west longitude. Howland Island’s CIA coordinates are 0 degrees 48 minutes north latitude, 176 degrees 38 minutes west longitude.

Except for Wake Island, the U.S. Minor Outlying Islands experiences the instant of the 2019 March equinox on Wednesday, March 20. Wake Island lies west of the International Date Line. The coral atoll comprising the three islands of Peale, Wake and Wilkes has an offset of UTC+12. The 2019 spring equinox happens Thursday, March 21, at 9:58 a.m., according to the Wake Island Time Zone. Wake Island’s CIA coordinates are 19 degrees 17 minutes north latitude, 166 degrees 39 minutes east longitude.

The takeaways for the 2019 March equinox are that American Samoa has an autumn equinox, along with Jarvis Island, as the only U.S. possessions in the Southern Hemisphere and that Wake Island is the only one of the nine U.S. Minor Outlying Islands with a Thursday, March 21, date for the equinoctial event.

Jarvis Island's western shore, with day beacon (white; right) and U.S. Fish and Wildlife Service’s No Trespassing sign (orange-brown; left); Central Pacific Ocean; Thursday, Oct. 16, 2003, 21:15: Joann94024 at English Wikipedia, Public Domain, via Wikimedia Commons

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

NASA’s DC-8 flying laboratory’s stop in American Samoa in summer 2016, during first round of Atom (Atmospheric Tomography) flights: NASA photo, Public Domain, via NASA @ https://www.nasa.gov/centers/armstrong/news/newsreleases/2017/17-02.html

Jarvis Island's western shore, with day beacon (white; right) and U.S. Fish and Wildlife Service’s No Trespassing sign (orange-brown; left); Central Pacific Ocean; Thursday, Oct. 16, 2003, 21:15: Joann94024 at English Wikipedia, Public Domain, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Jarvis_Island_Coast.JPG

For further information:

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Available @ https://earth-and-space-news.blogspot.com/2018/03/2018-northern-hemisphere-spring-equinox.html

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Available @ https://earth-and-space-news.blogspot.com/2019/03/2019-northern-hemisphere-spring-equinox.html

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Available @ https://earth-and-space-news.blogspot.com/2017/03/american-samoa-has-autumn-equinox-while.html

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Available @ https://earth-and-space-news.blogspot.com/2017/03/american-samoa-has-autumn-equinox-while.html

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Available @ https://earth-and-space-news.blogspot.com/2019/03/march-equinox-astronomically-opens.html

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Available @ https://www.cia.gov/library/publications/the-world-factbook/fields/2011.html

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Available @ https://www.cia.gov/library/publications/the-world-factbook/graphics/ref_maps/physical/pdf/standard_time_zones_of_the_world.pdf

U.S. Department of the Interior-Office of Insular Affairs. A Brief History of Swains Island in American Samoa.
Available via Internet Archive Wayback Machine @ https://web.archive.org/web/20120208205101/http://www.doi.gov/oia/Islandpages/swainsis.htm

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Available @ http://aa.usno.navy.mil/faq/docs/equinoxes.php

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