American Samoa Has Summer Solstice As Rest of U.S. Has Winter Solstice

Summary: American Samoa has a summer solstice as the rest of the U.S. has a winter solstice in December.

American Samoa’s five main islands (Aunu’u, Ofu, Olosega, Ta’u, Tutuila) and two atolls (Rose, Swains Island): U.S. Department of the Interior Geological Survey, The National Atlas of the United States of America (1970), Pacific Outlying Areas, page 53: USDI, Public Domain, via Wikimedia Commons

American Samoa has a summer solstice as the rest of the U.S. has a winter solstice in December because American Samoa and Jarvis Islands are the only parts of the United States lying in the Southern Hemisphere.

The Northern Hemisphere and the Southern Hemisphere experience opposite seasons. The annual December solstice announces astronomical winter in the Northern Hemisphere but opens astronomical summer in the Southern Hemisphere. Consequently, the December solstice is known as a winter solstice in the Northern Hemisphere and as a summer solstice in the Southern Hemisphere.

Jarvis Island joins American Samoa as the only parts of the United States positioned in the Southern Hemisphere. Both islands are sited in the South Pacific Ocean.

Coordinated Universal Time, the world’s time standard, places the instant of the 2018 December solstice at 22:22 UTC, Friday, Dec. 21. American Samoa and Jarvis Island have local times that lag 11 hours behind Coordinated Universal Time. UTC-11 represents the UTC time offset for American Samoa and Jarvis Island. The United States’ two Southern Hemisphere possessions experience the 2018 December solstice at 11:22 a.m., local time, Friday, Dec. 21.

Earth’s equator is closer to Jarvis Island than to American Samoa. Jarvis Island’s geographic coordinates are 0 degrees 22 minutes south latitude and 160 degrees 1 minute west longitude. The uninhabited coral island lies only 22 nautical miles (25.31 miles; 40.74 kilometers) south of the equator. The low-lying island’s location is about halfway between the Hawaii archipelago in the Central Pacific Ocean and the Cook Island archipelago in the South Pacific Ocean.

American Samoa is considered as the southernmost part of the United States. The archipelago of five main islands and two atolls lies southwest of Jarvis Island. American Samoa approximates the halfway point between the Hawaiian archipelago in the Northern Hemisphere and New Zealand’s main archipelago in the Southern Hemisphere.

American Samoa’s atolls and islands stretch from approximately 11 to 15 degrees south latitude and from approximately 168 to 171 degrees west longitude. Coral atoll Swains Island is American Samoa’s northernmost point. Rose Atoll claims the easternmost point in American Samoa and the southernmost point in the United States.

American Samoa observes Samoa Standard Time (SST). American Samoa’s time zone maintains a UTC offset of UTC-11 year-round. The unincorporated U.S. territory makes no adjustments for daylight savings.

Samoa Standard Time zone offers one of the earliest occurrences of the 2018 December solstice. The earliest occurrence of the 2018 December solstice, however, happens in the U.S. Minor Outlying Islands of Baker Island and Howland Island. Baker and Howland islands lag 12 hours behind Universal Coordinated Time and one hour behind Samoa Standard Time. The coral islands’ UTC offset of UTC-11 places the 2018 December solstice at 10:22 a.m. Anywhere on Earth (AoE) Time, Friday, Dec. 21. Their placement less than one degree north of the equator allow Baker and Howland to join the rest of the United States in experiencing the December solstice as an astronomical winter opener.

Not all islands in the U.S. Minor Outlying Islands observe the same local time. Midway Atoll observes Samoa Standard Time. Although observing the same time zone as American Samoa, Midway Atoll does not share the same seasons. The December solstice opens astronomical winter for the unorganized, unincorporated U.S. territory. Midway Atoll lies near the northwestern end of the Hawaiian archipelago. Yet, the atoll comprises the only island in the Hawaiian archipelago that is not part of the United States’ 50th state.

Wake Island occupies the westernmost point of the Pacific Ocean’s seven United States Minor Outlying Islands. Wake Time (WAKT) is 12 hours ahead of Coordinated Universal Time. The coral atoll’s UTC offset of UTC+12 places the 2018 December solstice at 10:22 a.m. WAKT, Saturday, Dec. 22. The December solstice opens astronomical winter for Wake Island.

The takeaway for American Samoa’s summer solstice as the rest of the U.S. has a winter solstice is that American Samoa and Jarvis Island are the only parts of the United States located in the Southern Hemisphere.

Jarvis Island and American Samoa are the only parts of the United States lying within the Southern Hemisphere: U.S. Department of the Interior Geological Survey, The National Atlas of the United States of America (1970), Pacific Outlying Areas, page 53: USDI, 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:

American Samoa’s five main islands (Aunu’u, Ofu, Olosega, Ta’u, Tutuila) and two atolls (Rose, Swains Island): U.S. Department of the Interior Geological Survey, The National Atlas of the United States of America (1970), Pacific Outlying Areas, page 53: USDI, Public Domain, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:National_Atlas_of_the_USA_1970_-_Pacific_Outlying_Areas.jpg?uselang=fr

Jarvis Island and American Samoa are the only parts of the United States lying within the Southern Hemisphere: U.S. Department of the Interior Geological Survey, The National Atlas of the United States of America (1970), Pacific Outlying Areas, page 53: USDI, Public Domain, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:National_Atlas_of_the_USA_1970_-_Pacific_Outlying_Areas.jpg?uselang=fr

For further information:

“Islands in the Pacific Ocean - Jarvis, Baker, and Howland Islands.” NOAA (National Oceanic and Atmospheric Administration) Charts > Booklet Chart™.
Available @ http://www.charts.noaa.gov/BookletChart/83116_BookletChart.pdf

Marriner, Derdriu. “American Samoa Has Autumn Equinox While United States Has Spring Equinox.” Earth and Space News. Wednesday, March 1, 2017.
Available @ https://earth-and-space-news.blogspot.com/2017/03/american-samoa-has-autumn-equinox-while.html

Marriner, Derdriu. “December Solstice Always Occurs at the Same Instant Everywhere on Earth.” Earth and Space News. Wednesday, Nov. 30, 2016.
Available @ https://earth-and-space-news.blogspot.com/2016/11/december-solstice-always-occurs-at-same.html

“PRIA: Jarvis Island.” Pacific Islands Benthic Habitat Mapping Center > Pacific Remote Island Area (PRIA).
Available @ http://www.soest.hawaii.edu/pibhmc/pibhmc_pria_jar.htm

U.S. Department of the Interior Geological Survey. The National Atlas of the United States of America. Washington DC: U.S. Geological Survey, 1970.
Available via Library of Congress @ https://www.loc.gov/item/79654043/