All dates are for Northern Hemisphere

(Movable dates are marked with *.)


Jan 1  New Year’s Day

Jan 1  Cosmic Calendar: Big Bang 13.8 billion years ago (bya)

* third Monday of January is Martin Luther King Day

Jan 22  Chief Seattle surrenders native land

Jan 27  International Holocaust Remembrance Day


Feb 1/2 Neo-Pagan winter cross-quarter day (Imbolc)

Feb 2  Groundhog’s Day

*Feb 3-4  Winter thermistice/cross-quarter

Feb 12  Darwin Day

Feb 17  Giordano Bruno burned at the stake

Feb 20  World Day of Social Justice

Feb 24  Black Nonbelievers Solidarity Day


Mar 4  Church of All Worlds charted as first Neo-Pagan church in U.S. (1967)

Mar 8  International Women’s Day

* second Sunday of March Daylight Savings Time begins in the U.S.

Mar 14  Einstein’s birthday /  Pi Day

Mar 15  Hypatia Day

Mar 17  St. Patrick’s Day

*Mar 19-20  Spring equinox ( spring begins in U.S.) / Neo-Pagan spring quarter day (Ostara)

Mar 21  International Day of Nowruz

Mar 21  International Day of the Forests

Mar 22  World Water Day


Apr 7  World Health Day

Apr 12  International Day of Human Space Flight

Apr 20  Marcus Aurelius’ birthday

Apr 21  John Muir’s birthday

Apr 22  Earth Day / International Mother Earth Day

Apr 25  Arbor Day


May 1  Neo-Pagan spring cross-quarter day (Beltane)

* first Thursday of May is National Day of Prayer and National Day of Reason

May 2  Pagan Coming Out Day

*May 4-5  Spring equitherm/cross-quarter

May 11  Cosmic Calendar: Milky Way Galaxy Formed 8.8 bya

May 15  Thomas Taylor’s birthday

May 16  Love a Tree Day

May 22  International Day for Biological Diversity

May 24  Vesak, Day of the Full Moon

* last Monday of May is Memorial Day, unofficial start of summer in U.S.


Jun 5  World Environment Day

Jun 8  World Oceans Day

Jun 20  World Refugee Day

Jun 20-21  Summer solstice (summer begins in U.S.) / Neo-Pagan summer quarter day (Litha) and World Humanist Day

Jun 26  Julian, the last pagan emperor’s birthday

Jun 26  Anniversary of the U.S. Supreme Court same-sex equal rights cases


Jul 11  World Population Day

Jul 12  Malala Day

Jul 18  Nelson Mandela Day

Jul 20  Anniversary of the Moon Landing


Aug 1  Neo-Pagan summer cross-quarter day (Lughnasadh)

Aug 6  Hiroshima Day

*Aug 6-7 Summer thermistice/cross-quarter

Aug 9  International Indigenous Peoples Day

Aug 19  World Humanitarian Day

Aug 24  Anniversary of Look magazine issue featuring a Neo-Pagan Beltane ritual (1971)

Aug 25  Death of Friedrich Nietzsche


Sept 1  Cosmic Calendar: Sun formed 4.57 bya

* first Monday in September is Labor Day, unofficial end of summer in U.S.

Sept 4  Anniversary of Dettmer v. Landon, Wicca legally recognized as a religion

Sept 6  Neo-Pagan Tim Zell has his Theagenesis vision (1971), predating the popularization of Lovelock’s Gaia hypothesis

Sept 9  Emerson publishes his essay “Nature”, unofficial beginning of Transcendentalism

Sept 11  9-11 / Anniversary of the World Trade Center attacks

Sept 13  Defy Superstition Day

Sept 15  International Day of Democracy

Sept 16  Cosmic Calendar: Oldest rocks known on earth date to 4 bya

Sept 21  World Peace Day

Sept 21 Cosmic Calendar: First life emerges (prokaryotes) 3.8 bya

*Sept 22-23  Autumn equinox (fall begins in U.S.) / Neo-Pagan autumn quarter day (Mabon)

Sept 30  Blasphemy Rights Day


Oct 2  Gandhi’s birthday and International Day of Non-Violence

* first Monday in October is World Habitat Day

Oct 12  Cosmic Calendar: First photosynthesis occurs 3 bya

Oct 16  World Food Day

Oct 17  International Day for the Eradication of Poverty

Oct 29  Cosmic Calendar: Oxygenation of atmosphere occurs 2.4 bya

Oct 31/Nov 1  Neo-Pagan autumn cross-quarter day (Samhain) / Halloween

Oct 31  Anniversary of the publication of The Spiral Dance and Drawing Down the Moon


* first Sunday in November Daylight Savings Time ends in U.S.

*Nov 6-7  Autumn equitherm/cross-quarter

Nov 8  Cosmic Calendar: First complex cells (eukaryotes) emerge 2 bya

Nov 9  Carl Sagan’s birthday

Nov 16  International Day of Tolerance

* third Thursday in November is World Philosophy Day

Nov 24  Spinoza’s birthday

Nov 25  International Day for the Elimination of Violence Against Women

Nov 30  John Toland’s birthday


Dec 3  International Day of Persons with Disabilities

Dec 5  Cosmic Calendar: First multicellular life 1 bya

Dec 7  Apollo 17 crew photographs “The Blue Marble” photo

Dec 10  International Human Rights Day

Dec 14  Cosmic Calendar: Simple animals emerge 0.67 bya

Dec 14  Cosmic Calendar: Arthropods emerge 0.55 bya

Dec 18  Cosmic Calendar: Fish and proto-amphibians emerge 0.5 bya

Dec 20  Cosmic Calendar: Land plants emerge 0.45 bya

*Dec 21-22  Winter solstice (winter begins in U.S.) / Neo-Pagan winter quarter day (Yule)

Dec 21  Cosmic Calendar: Insects and seeds emerge 0.4 bya

Dec 22  Cosmic Calendar: Amphibians emerge 0.36 bya

Dec 23  Cosmic Calendar: Reptiles and dinosaurs emerge 0.3 bya

Dec 24  Apollo 8 crew photograph’s “Earthrise” photo

Dec 25  Newton’s birthday

Dec 26  Cosmic Calendar: Mammals emerge 0.2 bya

Dec 27  Cosmic Calendar: Birds emerge 0.15 bya

Dec 27  Anniversary of the voyage of the Beagle

Dec 28  Cosmic Calendar: Flowers emerge 0.13 bya

Dec 30  Cosmic Calendar: Cretaceous-Paleogene extinction event (non-avian dinosaurs die out) 65 mya

Dec 30  Cosmic Calendar: Primates emerge 65 mya

Dec 31  Cosmic Calendar: Hominids emerge 15 mya


The Cosmic Calendar presented above, which maps the history of the universe onto a single year, comes from Carl Sagan’s The Dragons of Eden. An alternative is the Earth Story Calendar, which presents an unfolding which is similar, but spaced out a bit more evenly.

4 Comments on “Calendar

  1. Pingback: Looking back, Looking forward | Humanistic Paganism

  2. Pingback: Cosmic Calendar Special | Humanistic Paganism

  3. December is certainly a busy month for evolutionary changes, but it’s worth noting that life began on September 21 and has thus been around for more than a quarter of the entire time since the Big Bang. I think of the big division of our “life span” as the oxygenation of the planet that falls almost in the middle, on October 29. Before that date, only small, simple single cells; after it, complexity and growth. Then, as now, life changed as the planet changed.


  4. Pingback: Cosmic Calendar Countdown -


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