Science Series: Summer Solstice

Science of the Summer Solstice

The Start of Summer

Bill Petro
4 min readJun 22, 2024

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Summer Solstice. Image: Wikipedia

Solstice comes from the Latin word solstitium, meaning “Sun, standing still.” The Summer Solstice occurs on June 20 at 20:51 UTC, Coordinated Universal Time, Zulu Time, or roughly Greenwich Mean Time. Greenwich, England, is the prime meridian — the zero point for longitude lines.

Why is UTC the abbreviation for Coordinated Universal Time?

The acronym came about as a compromise between English and French speakers: Coordinated Universal Time would normally be abbreviated as CUT, and the French name Temps Universel Coordonné would be TUC.

Summer Time and the Summer Solstice

This is also known as the Northern Solstice because the Sun is positioned directly above the Tropic of Cancer in the Northern Hemisphere.

  • This time of year is known as Midsummer, though the official Midsummer Day is actually celebrated on June 24, thanks to differences between the Julian and Gregorian calendars.
  • Christian festivals are held during this time of year related to the Birth of St. John the Baptist. In Bolivia and Peru, it’s called the Festival of San Juan.

Does Summer Start on the Summer…

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Bill Petro

Writer, historian, technologist. Former Silicon Valley tech exec. Author of fascinating articles on history, tech, pop culture, & travel. https://billpetro.com