# Science of the Summer Solstice: Start of Summer > SCIENCE OF THE SUMMER SOLSTICE olstice comes from the Latin word solstitium, meaning "Sun, standing still." The Summer Solstice occurs on June 20 at 10:22 PM EDT. But for our European friends and those farther east, it's on June 21… > URL: https://billpetro.com/science-of-the-summer-solstice/ > Last modified: 2026-06-19T03:02:10+00:00 Reading Time: 3 minutes ## [](https://www.billpetro.com/wp-content/uploads/SummerSolstice-700314)SCIENCE OF THE SUMMER SOLSTICE **Solstice** comes from the Latin word *solstitium,* meaning “Sun, standing still.” The Summer Solstice occurs on *June 20 at 10:22 PM EDT.* But for our European friends and those farther east, it’s on June 21 at 08:25 UTC (Coordinated Universal Time, or Zulu Time, 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](https://www.timeanddate.com/time/utc-abbreviation.html): **C**oordinated **U**niversal **T**ime would normally be abbreviated as CUT, and the French name ***T**emps **U**niversel **C**oordonné* would be TUC.   Table of Contents Toggle - [Summer Time and the Summer Solstice](#Summer_Time_and_the_Summer_Solstice) - [Does Summer Start on the Summer Solstice?](#Does_Summer_Start_on_the_Summer_Solstice) - [The Solstice in the Summer Solstice](#The_Solstice_in_the_Summer_Solstice) - [Summer Solstice Know-It-All Facts to impress your friends and neighbors:](#Summer_Solstice_Know-It-All_Facts_to_impress_your_friends_and_neighbors) - [Related](#Related) ### 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**](https://billpetro.com/st-john-the-baptist/) is actually celebrated on June 24, thanks to differences between the Julian and Gregorian calendars. - Christian festivals are held during this time of year in honor of the [**Birth of St. John the Baptist**](https://billpetro.com/st-john-the-baptist/). In Bolivia and [Peru](https://billpetro.com/lets-float-down-to-peru/), it’s called the **Festival of San Juan**.   ### Does Summer Start on the Summer Solstice? Short answer: *Yes.* Longer Answer: *And… * Have you noticed how some people declare the “unofficial” start of Summer following [**Memorial Day**](https://billpetro.com/history-of-memorial-day-which-war) at the end of May? Even though that’s more a school-calendar tradition than an astronomical one, there’s actually some science behind a *different* early-summer marker… While the Solstice is the beginning of the *astronomical Summer*, **[June 1st](https://billpetro.com/history-of-june/)** is the beginning of the *meteorological Summer.*     *What is meteorological Summer, and how does it differ*? - *Astronomical* seasons are based on Earth’s position relative to the Sun, which I’ll explain below. - *Meteorological* seasons are based on the annual temperature cycle. Astronomy is an ancient science, and modern meteorology is more recent. Significant progress was not seen until the 18th and 19th centuries. It has risen in popularity due to climate studies. Meteorological observation and forecasting led to the creation of these *meteorological* seasons, which are more closely tied to our monthly civil calendar than the *astronomical* seasons. According to the [**National Centers for Environmental Information**](https://www.ncei.noaa.gov/news/meteorological-versus-astronomical-seasons), each season ranges from 90 days for the Winter of a non-leap year to 92 days for Spring and Summer.     Meteorologists and climatologists divide the seasons into three-month groupings based on the annual temperature cycle and our calendar. Meteorological Spring in the Northern Hemisphere includes March, April, and May; **meteorological Summer** includes June, July, and August; meteorological Fall includes September, October, and November; and meteorological Winter includes December, January, and February.   ### The Solstice in the Summer Solstice Earth enjoys different seasons because it is tilted 23 degrees and 27 minutes away from the perpendicular to the plane of its orbit. This means that the Earth rotates like a tilted spinning top. The Summer Solstice is the longest day of sunlight, as the Sun is at its highest arc in the sky, at least in the Northern Hemisphere. The farther north one is from the Equator, the more pronounced this is in Summer. However, as the Earth continues its orbit, the hemisphere tilted toward the Sun changes, and the seasons reverse. *I was in Iceland at the beginning of June. The sun “set” at 11:30 pm and “rose” at 3:30 am. It never got fully dark.* In the Northern Hemisphere, the Sun appears at its highest point in the sky, and its noontime elevation seems to be the same for several days before and after the Solstice. So, it looks like the Sun is “standing still” until following the Summer Solstice, when the days begin to grow shorter and the nights longer.   ### Summer Solstice Know-It-All Facts to impress your friends and neighbors: - The Summer Solstice is *not* the longest day of the year, only the one with the most *daylight*. The longest day (no relation to the [movie](https://billpetro.com/history-of-d-day#:~:text=I%20remember%20as%20a%20boy%20watching%20with,Mitchum%2C%20and%20(a%20pre-James%20Bond)%20Sean%20Connery.)) is in November, when we “fall back” to [Daylight Saving Time](https://billpetro.com/history-of-daylight-saving-time-ending) and gain an extra hour, making the day 25 hours long. - The Earth is actually *farthest* from the Sun in the Summer. Earth’s aphelion (farthest point from the Sun) occurs in **early July** - Your noontime shadow is the shortest of the year on the Summer Solstice - Fairbanks, Alaska, gets almost 24 hours of sunlight on the Summer Solstice. They routinely have an annual midnight baseball game.   Bill Petro, your friendly neighborhood historian [billpetro.com](https://billpetro.com) [*Subscribe*](http://g003.enterprise.ipost.com/billpetrofriend/prefs) to have future articles delivered to your email.  ### *Related* [](https://www.addtoany.com/add_to/facebook?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-the-summer-solstice%2F&linkname=Science%20of%20the%20Summer%20Solstice%3A%20Start%20of%20Summer)[](https://www.addtoany.com/add_to/x?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-the-summer-solstice%2F&linkname=Science%20of%20the%20Summer%20Solstice%3A%20Start%20of%20Summer)[](https://www.addtoany.com/add_to/pinterest?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-the-summer-solstice%2F&linkname=Science%20of%20the%20Summer%20Solstice%3A%20Start%20of%20Summer)[](https://www.addtoany.com/add_to/linkedin?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-the-summer-solstice%2F&linkname=Science%20of%20the%20Summer%20Solstice%3A%20Start%20of%20Summer)[](https://www.addtoany.com/add_to/mastodon?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-the-summer-solstice%2F&linkname=Science%20of%20the%20Summer%20Solstice%3A%20Start%20of%20Summer)[](https://www.addtoany.com/add_to/threads?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-the-summer-solstice%2F&linkname=Science%20of%20the%20Summer%20Solstice%3A%20Start%20of%20Summer)[](https://www.addtoany.com/add_to/bluesky?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-the-summer-solstice%2F&linkname=Science%20of%20the%20Summer%20Solstice%3A%20Start%20of%20Summer)[](https://www.addtoany.com/add_to/reddit?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-the-summer-solstice%2F&linkname=Science%20of%20the%20Summer%20Solstice%3A%20Start%20of%20Summer)[](https://www.addtoany.com/add_to/tumblr?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-the-summer-solstice%2F&linkname=Science%20of%20the%20Summer%20Solstice%3A%20Start%20of%20Summer)[](https://www.addtoany.com/add_to/kindle_it?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-the-summer-solstice%2F&linkname=Science%20of%20the%20Summer%20Solstice%3A%20Start%20of%20Summer)[](https://www.addtoany.com/add_to/snapchat?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-the-summer-solstice%2F&linkname=Science%20of%20the%20Summer%20Solstice%3A%20Start%20of%20Summer)[](https://www.addtoany.com/add_to/email?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-the-summer-solstice%2F&linkname=Science%20of%20the%20Summer%20Solstice%3A%20Start%20of%20Summer)[](https://www.addtoany.com/add_to/print?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-the-summer-solstice%2F&linkname=Science%20of%20the%20Summer%20Solstice%3A%20Start%20of%20Summer)[](https://www.addtoany.com/share)