City history
Founded in 1325 as Mexico-Tenochtitlan, Mexico City evolved from indigenous mountain solar observatories to Central Standard Time.
Chapter one
Indigenous name
"In the navel of the moon / Place of the prickly pear cactus"
Founded by the Mexica people around 1325 on an island in Lake Texcoco, the name combines references to their protective deity Mexitli and the place of the prickly pear cactus.
In the navel of the moon / Place of the prickly pear cactus
Capital city of the Mexica Empire built on an island in Lake Texcoco.
City of Mexico
Established by Spanish colonizers atop the destroyed ruins of Tenochtitlan.
Federal District
Designated as the federal seat of government for independent Mexico.
Mexico City (CDMX)
Re-established as an autonomous federal entity with its own constitution.
Chapter two
Mexico officially introduced standard time zones on January 1, 1922. Mexico City transitioned from Tacubaya Observatory local mean solar time (GMT-6:36:36) to standard time based on the 105th Meridian West.
On November 15, 1928, Mexico City moved from the 105th Meridian West (GMT-7) to the 90th Meridian West (GMT-6), permanently aligning the nation's capital with Central Standard Time.
Mexico introduced national daylight saving time in 1996. Mexico City advanced its clocks by one hour to Central Daylight Time (UTC-5) each spring, returning to standard time in autumn.
Mexico's Congress enacted legislation ending daylight saving time across most of the country. On October 30, 2022, Mexico City adjusted clocks back one final time to remain permanently on Central Standard Time (UTC-6).
Chapter three
The Mexica established their capital in Lake Texcoco, utilizing sunrise alignments over Mount Tlaloc and surrounding mountain peaks to maintain an extraordinarily accurate solar agricultural calendar.
Workers conducting repairs on the Mexico City Cathedral unearthed the 24-ton Piedra del Sol, a carved Mexica monolith depicting Mesoamerican cosmic eras, solar cycles, and ritual calendrical symbols.
Mexico founded its National Astronomical Observatory at Chapultepec Castle, relocating to Tacubaya in 1883, where astronomers provided precise astronomical calculations and defined local mean time for the capital.
The Ottoman Arab immigrant community presented a grand clock tower in downtown Mexico City to celebrate the Mexican Independence Centennial, featuring traditional tilework and dual numerical dials.
The inauguration of Line 1 between Chapultepec and Zaragoza brought rapid underground mass transit and synchronized electronic station clocks, modernizing public timekeeping for millions of daily commuters.