June 20 Solstice Opes Northern Astronomical Summer and Southern Winter

Summary: With a north polar tilt toward the sun, the June 20, 2024, solstice simultaneously opes northern astronomical summer and southern astronomical winter.

Graphic of Northern Hemisphere's summer solstice depicts axial tilting toward sun favoring Northern Hemisphere and compares highest solar placements in the sky on equinoxes and solstices: via NOAA National Weather Service

With Earth's North Pole tilting toward the sun, the June 20, 2024, solstice simultaneously opes the astronomical seasons of summer in the Northern Hemisphere and winter in the Southern Hemisphere.

The June solstice in 2024 takes place Thursday, June 20, at 4:51 p.m. Eastern Daylight Time (EDT) in the Northern Hemisphere. The time of the Earth-wide event corresponds to Thursday, June 20, at 20:51 Coordinated Universal Time (UTC), the Earth's primary time standard, according to the U.S. Naval Observatory, Astronomical Applications Department's "Earth Seasons -- Equinoxes and Solstices -- 2023-2026," published on the National Oceanic and Atmospheric Administration's (NOAA) National Weather Service website. The equinox occurs on Thursday, June 20, for the first three (UTC+1 through UTC+3) of the 14 time zones that lie east of UTC. It happens Friday, June 21, for the last nine (UTC+4 through UTC+14) of the time zones east of UTC. The equinox appears of Thursday, June 20, for all 12 time zones lying west of UTC, according to "Time Zone Converter -- Time Difference Calculator (Classic)," published on the Time and Date website.

A positive UTC offset, formatted as UTC+1 through UTC+14, references time zones east of UTC. A negative UTC offset, symbolized as UTC-1 through UTC-12, indicates time zones west of UTC. Time zones east of UTC are ahead of UTC. Time zones west of UTC lag behind UTC.

The June solstice pairs with the year's December solstice in opening the astronomical seasons of summer and winter. The December solstice flips the June solstice's hemispheric seasonal assignments. Accordingly, the December solstice initiates astronomical winter in the Northern Hemisphere and astronomical summer in the Southern Hemisphere.

"But what is the solstice exactly?" asks NASA Jet Propulsion Laboratory web producer, editor and writer Jessica Stoller-Conrad in "What Is a Solstice?" on the National Oceanic and Atmospheric Administration's (NOAA) SciJinks website. The solstices are associated with "imaginary lines on our planet," such as the equator, Earth's axis of rotation and the "special" tropical latitudinal circles of Cancer in the Northern Hemisphere and Capricorn in the Southern Hemisphere.

June's solstice links with the Northern Hemisphere's Tropic of Cancer. December's solstice connects with the Southern Hemisphere's Tropic of Capricorn. The year's two solstices represent a directly overhead sun at high noon, i.e., 12:00 p.m., at the respective circle of latitude. Accordingly, the sun appears directly above the Tropic of Cancer on the June solstice and directly above the Tropic of Capricorn on the December solstice.

These two imaginary circles mark, respectively, the northernmost and southernmost latitudes for a directly overhead sun at high noon. "Outside the tropic zones, whether to the south or north, the sun is never directly overhead," explains Jessica Stoller-Conrad.

The year's two solstices share responsibility for the astronomical seasons with the year's two equinoxes, which occur in March and September. The March equinox occasions astronomical spring in the Northern Hemisphere and astronomical autumn in the Southern Hemisphere. March's complement, September's equinox, ushers astronomical autumn in the Northern Hemisphere and astronomical spring in the Southern Hemisphere.

Equinoxes and solstices sequence alternately, every three months, in each year. The year's first equinox appears in March. Three months later, the year's first solstice happens in June. The second of the year's two equinoxes occurs three months later, in September. Finally, the second of the year's two solstices takes place in December, three months after September's equinox.

In 2024, as the successor of June's solstice, September's equinox is scheduled for Sunday, Sep. 22, 2024, at 8:44 a.m. EDT (12:44 UTC). September's equinox is timed for Monday, Sep. 23, for the last three (UTC+12 through UTC+14) of the 14 time zones lying east of UTC.

December's solstice occurs as the year's final astronomical season opener. In 2024, the year's last solstice is slated for Saturday, Dec. 21, at 4:21 a.m. Eastern Standard Time (EST) and at 09:21 UTC. December's solstice is slated for Sunday, Dec. 22, for the last three (UTC-10 through UTC-12) of the 12 time zones lying west of UTC.

The National Oceanic and Atmospheric Administration's (NOAA) GOES (Geostationary Operational Environmental Satellites) East and West satellites imaged Earth moments after the June 2019 solstice's occurrence Friday, June 19, at 1:54 a.m. Eastern Daylight Time (03:54 Coordinated Universal Time UTC): via NOAA NESDIS (National Environmental Satellite, Data, and Information Service)

Acknowledgment

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

Dedication

This post is dedicated to the memory of our beloved blue-eyed brother, Charles, who guided the creation of the Met Opera and Astronomy posts on Earth and Space News. We memorialized our brother in "Our Beloved Blue-Eyed Brother, Charles, With Whom We Are Well Pleased," published on Earth and Space News on Thursday, Nov. 18, 2021, an anniversary of our beloved father's death.

Image credits:

Graphic of Northern Hemisphere's summer solstice depicts axial tilting toward sun favoring Northern Hemisphere and compares highest solar placements in the sky on equinoxes and solstices: via NOAA National Weather Service @ https://www.weather.gov/unr/summer_solstice

The National Oceanic and Atmospheric Administration's (NOAA) GOES (Geostationary Operational Environmental Satellites) East and West satellites imaged Earth moments after the June 2019 solstice's occurrence Friday, June 19, at 1:54 a.m. Eastern Daylight Time (03:54 Coordinated Universal Time UTC): via NOAA NESDIS (National Environmental Satellite, Data, and Information Service) @ https://www.nesdis.noaa.gov/news/goes-east-and-west-see-the-summer-solstice

For further information:

Alberge, Dalya. "Stonehenge was built on solstice axis, dig confirms." The Guardian > Culture. Sep. 8, 2013.
Available @ https://www.theguardian.com/culture/2013/sep/08/stonehenge-ice-age-solstice-axis

Editors of EarthSky. "2024 June solstice: All you need to know." EarthSky > Tonight > Astronomy Essentials. June 19, 2024.
Available via EarthSky @ https://earthsky.org/astronomy-essentials/everything-you-need-to-know-june-solstice/

Marriner, Derdriu. "12 Days After June Solstice Earth Reaches 2017 Aphelion Monday, July 3." Earth and Space News. Wednesday, June 28, 2017.
Available @ https://earth-and-space-news.blogspot.com/2017/06/12-days-after-june-solstice-earth.html

Marriner, Derdriu. "2016 June Solstice Signals Summer Start But Also Begins Summer End." Earth and Space News. Wednesday, June 15, 2016.
Available @ https://earth-and-space-news.blogspot.com/2016/06/2016-june-solstice-signals-summer-start.html

Marriner, Derdriu. "2017 June Solstice Happens Tuesday, June 20, or Wednesday, June 21." Earth and Space News. Wednesday, June 21, 2017.
Available @ https://earth-and-space-news.blogspot.com/2017/06/2017-june-solstice-happens-tuesday-june.html

Marriner, Derdriu. "2018 June Solstice Happens Thursday, June 21, or Friday, June 22." Earth and Space News. Wednesday, June 20, 2018.
Available @ https://earth-and-space-news.blogspot.com/2018/06/2018-june-solstice-happens-thursday.html

Marriner, Derdriu. "2019 June Solstice Happens Friday, June 21, or Saturday, June 22." Earth and Space News. Wednesday, June 12, 2019.
Available @ https://earth-and-space-news.blogspot.com/2019/06/2019-june-solstice-happens-friday-june.html

Marriner, Derdriu. "First 2023 Solstice Happens Wednesday, June 21, at 14:58 UTC." Earth and Space News. Wednesday, June 7, 2023.
Available @ https://earth-and-space-news.blogspot.com/2023/06/first-2023-solstice-happens-wednesday.html

Marriner, Derdriu. "Full Strawberry Blue Moon Seasonally Welcomes 2016 June Solstice." Earth and Space News. Wednesday, June 8, 2016.
Available @ https://earth-and-space-news.blogspot.com/2016/06/full-strawberry-blue-moon-seasonally.html

Marriner, Derdriu. "June 21, 2023, Solstice Is Wintry for American Samoa and Jarvis Island." Earth and Space News. Wednesday, June 14, 2023.
Available @ https://earth-and-space-news.blogspot.com/2023/06/june-21-2023-solstice-is-wintry-for.html

Marriner, Derdriu. "June Signals Winter Solstice for American Samoa and Jarvis Island." Earth and Space News. Wednesday, June 19, 2019.
Available @ https://earth-and-space-news.blogspot.com/2019/06/june-signals-winter-solstice-for.html

Marriner, Derdriu. "March Equinox 2024 Happens Tuesday, March 19, or Wednesday, March 20." Earth and Space News. Wednesday, March 6, 2024.
Available @

Marriner, Derdriu. "Martian New Year and Summer Solstice 2015: Happy New Year From Mars." Earth and Space News. Saturday, June 20, 2015.
Available @ https://earth-and-space-news.blogspot.com/2015/06/martian-new-year-and-summer-solstice.html

Marriner, Derdriu. "Moon Reaches June Apogee 27 Hours After June 21, 2023, Solstice." Earth and Space News. Wednesday, June 21, 2023.
Available @ https://earth-and-space-news.blogspot.com/2023/06/moon-reaches-june-apogee-27-hours-after.html

Marriner, Derdriu. "Northern Hemisphere 2017 Summer Solstice Happens Wednesday, June 21." Earth and Space News. Wednesday, June 14, 2017.
Available @ https://earth-and-space-news.blogspot.com/2017/06/northern-hemisphere-2017-summer.html

Marriner, Derdriu. "Two Weeks After 2016 June Solstice Earth Reaches 2016 Aphelion." Earth and Space News. Wednesday, June 29, 2016.
Available @ https://earth-and-space-news.blogspot.com/2016/06/two-weeks-after-2016-june-solstice.html

NOAA Education. "Changing seasons." National Oceanic and Atmospheric Administration Education > Resources > Climate > Changing seasons.
Available via NOAA Education @ https://www.noaa.gov/education/resource-collections/climate/changing-seasons

NOAA National Weather Service. "Summer Arrives Today." NOAA National Weather Service.
Available via NOAA National Weather Service @ https://www.weather.gov/unr/summer_solstice

NOAA NESDIS. "GOES East and West see the summer solstice." NOAA NESDIS > News. June 21, 2019.
Available via NOAA NESDIS (National Environmental Satellite, Data, and Information Service) @ https://www.nesdis.noaa.gov/news/goes-east-and-west-see-the-summer-solstice

Stoller-Conrad, Jessica. "What Is a Solstice?" NOAA SciJinks > Topics > Weather Forecasting. Updated Oct. 3, 2023.
Available via NOAA SciJinks @ https://scijinks.gov/solstice/

Stoller-Conrad, Jessica. "Why Does Earth Have Seasons?" NOAA SciJinks > Topics > Weather Forecasting. Updated Oct. 3, 2023.
Available via NOAA SciJinks @ https://scijinks.gov/earths-seasons/

U.S. Naval Observatory, Astronomical Applications Department. "Earth Seasons -- Equinoxes and Solstices -- 2023-2026." NOAA National Weather Service.
Available via NOAA National Weather Service @ https://www.weather.gov/media/ind/seasons.pdf