Blue Moon Saturday, March 31, Is Second 2018 Calendrical Blue Moon

Summary: The blue moon Saturday, March 31, is the second 2018 calendrical blue moon, as the double blue moon year twice has two full moons in the same month.

Blue moon Saturday, March 31, is double blue moon year 2018’s second blue moon: EarthSky @earthskyscience, via Twitter Feb. 5, 2018

The blue moon Saturday, March 31, at 12:37 Coordinated Universal Time (8:37 a.m. Eastern Daylight Time), is the second 2018 calendrical blue moon, as the double blue moon year twice experiences two full moons in the same month.

March’s first full moon Friday, March 2, at 00:51 UTC (Thursday, March 1, at 7:51 p.m. Eastern Standard Time), opens the year’s second blue moon month. March’s blue, or second full, moon closes the month.

The double blue moon year’s first blue moon happened in January. January's first full moon appeared Tuesday, Jan. 2, at 02:24 UTC (Monday, Jan. 1, at 9:24 p.m. EST). The year’s first blue moon occurred as the month’s second full moon Wednesday, Jan. 31, at 13:27 UTC (8:27 a.m. EST).

January’s blue moon participated in the year’s first of two total lunar eclipses. The blue moon total lunar eclipse opened 2018’s eclipse quartet comprising two total lunar eclipses and three partial solar eclipses.

Both of 2018’s blue moons happen as calendrical blue moons by appearing as the second of two full moons within the same month. Another type of blue moon appears seasonally. A seasonal blue moon occurs as the third of four full moons taking place within three months in the same season.

March’s two full moons share the month with the March equinox (Latin: aequus, “equal” + nox, “night”). The month’s astronomical seasonal event is known as the vernal (Latin: vernalis, “of or pertaining to spring”), or spring, equinox in the Northern Hemisphere and as the autumnal equinox in the Southern Hemisphere. March’s equinox opens astronomical spring in the Northern Hemisphere and astronomical autumn in the Southern Hemisphere.

March’s equinox happens Tuesday, March 20, at 16:15 UTC (12:15 p.m. EDT). The astronomical seasonal event occurs 18 days 15 hours 24 minutes after the month’s first full moon.

March’s first full moon occurs as the third of three full moons falling between 2017’s fourth astronomical seasonal event, the December solstice, and 2018’s first astronomical seasonal event, the March equinox. January’s two full moons numbered as the first two full moon occurrences after the December solstice.

The December solstice took place Thursday, Dec. 21, at 16:29 UTC (11:29 a.m. EST). December’s solstice opened astronomical winter in the Northern Hemisphere and astronomical summer in the Southern Hemisphere. The December solstice is also known as the winter solstice in the Northern Hemisphere and as the summer solstice in the Southern Hemisphere.

March’s equinox precedes the month’s blue moon by 10 days 20 hours 22 minutes. March 2018’s blue moon numbers as the first of three full moons occurring between the year’s first two astronomical seasonal events, the March 2018 equinox and June’s solstice. Full moons Monday, April 30, at 00:58 UTC (Sunday, April 29, at 8:58 p.m. EDT), and Tuesday, May 29, at 14:20 UTC (10:20 a.m. EDT) complete the full moon trio occurring within northern spring and southern autumn.

The June solstice takes place June 21, at 10:07 UTC (6:07 a.m. EDT). June’s solstice opens astronomical summer in the Northern Hemisphere and astronomical winter in the Southern Hemisphere. The June solstice is also known as the summer solstice in the Northern Hemisphere and as the winter solstice in the Southern Hemisphere.

The takeaway for the blue moon Saturday, March 31, is that the second 2018 calendrical blue moon’s appearance as the first full moon after March’s equinox qualifies it as the first full moon of Northern Hemisphere’s spring and Southern Hemisphere’s autumn.

Double blue moon year 2018 offers blue moons in January and again in March: Brett Anthony @BrettKCTV5, via Twitter Jan. 30, 2018

Acknowledgment

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

Image credits:

Blue moon Saturday, March 31, is double blue moon year 2018’s second blue moon: EarthSky @earthskyscience, via Twitter Feb. 5, 2018, @ https://twitter.com/earthskyscience/status/960577015832371200

Double blue moon year 2018 offers blue moons in January and again in March: Brett Anthony @BrettKCTV5, via Twitter Jan. 30, 2018, @ https://twitter.com/BrettKCTV5/status/958354954875437056

For further information:

Espenak, Fred. “2018 Calendar of Astronomical Events Greenwich Mean Time.” Astro Pixels > Ephemeris.
Available @ http://astropixels.com/ephemeris/astrocal/astrocal2018gmt.html

Espenak, Fred. “Phases of the Moon: 2001 to 2100 Universal Time.” Astro Pixels > Ephemeris > Moon.
Available @ http://www.astropixels.com/ephemeris/phasescat/phases2001.html

Harper, David, and L.M. Stockman. “Once in a Blue Moon: The Double Blue Moon of 2018.” Obliquity > Interactive Astronomy.
Available @ https://www.obliquity.com/astro/blue2018.html

Marriner, Derdriu. “Blue Moon Month January 2018 Opens New Year With Two Full Moons.” Earth and Space News. Wednesday, Dec. 27, 2017.
Available @ https://earth-and-space-news.blogspot.com/2017/12/blue-moon-month-january-2018-opens-new.html

Marriner, Derdriu. “First 2018 Eclipse Is Blue Moon Total Lunar Eclipse Wednesday, Jan. 31.” Earth and Space News. Wednesday, Jan. 24, 2018.
Available @ https://earth-and-space-news.blogspot.com/2018/01/first-2018-eclipse-is-blue-moon-total.html

Marriner, Derdriu. “First March Full Moon Friday, March 2, Opens Second 2018 Blue Moon Month.” Earth and Space News. Wednesday, Feb. 28, 2018.
Available @ https://earth-and-space-news.blogspot.com/2018/02/first-march-full-moon-friday-march-2.html

Marriner, Derdriu. “2018 Northern Hemisphere Spring Equinox Happens Tuesday, March 20.” Earth and Space News. Wednesday, March 14, 2018.
Available @ https://earth-and-space-news.blogspot.com/2018/03/2018-northern-hemisphere-spring-equinox.html

Marriner, Derdriu. “Super Blue Moon Wednesday, Jan. 31, Is First of Two 2018 Blue Moons.” Earth and Space News. Wednesday, Jan. 31, 2018.
Available @ https://earth-and-space-news.blogspot.com/2018/01/super-blue-moon-wednesday-jan-31-is_31.html