Summer Begins Sunday! Really?

By Jack Williams ©2015
Areas of light and dark at the June 21 summer solstice.  U.S. Naval Observatory image.

Areas of light and dark at the June 21 summer solstice. U.S. Naval Observatory image.

With the (Northern Hemisphere) summer solstice coming up Sunday you’ll be hearing and reading about June 21 being “the official first day of summer.”

Balderdash! For years writers and broadcasters have been calling the June solstice “the official beginning of summer” and the December solstice “the official beginning of winter.” I’ve never found anyone, or any written source, that explains why the date is an “official” anything.

As Jan Null asks in his “First day of summer…kind of” posting on his San Francisco Weather Examiner blog: “…what makes it official?”

I’m so sure that there’s nothing “official” about these dates being the beginning of seasons that I’m making an offer: I will send (postage paid) a signed copy of my new AMS Weather Book to the first person to send me information about a law adopted by the U.S. Congress and signed by the President, or even a Presidential proclamation, making the solstices the “official” beginning of summer or winter.

To win, you need to send me a title for such a law or proclamation and the date it was signed so I can check it out. You can send the information by using the “Ask Jack a Question” form.

This “official beginning” business leads to foolishness such as calling a string of four or five very hot days ending on June 20 a “summer -like” heat wave. Common sense tells you that a heat wave is a heat wave and one during the first two-thirds of June is not at all strange.

Keith C. Heidorn sums this point up nicely in his The Wheel of the Year on his Weather Doctor Web site:  “The media in North America have taken these astronomical moments to signal an “official” starts for the Spring, Summer, Autumn and Winter weather seasons, as if some Arthurian decree had been issued from Camelot across the land. But the atmosphere does not follow human, or heavenly decree, promptly or with regularity.”

Even more importantly, such foolishness leads many people to think that “they” (the mysterious folks who set the official seasons) are out of touch with the real world.

One thing I can assure you of, “they” are not meteorologists. For North American meteorologists, and probably others around the Northern Hemisphere, summer is the months of June, July, and August. This does not imply that meteorologists think that nature turns some kind of switch on June 1 that immediately changes the weather. It does enable meteorologists to calculate seasonal averages for temperature and precipitation.

The fixation with the “official” beginning usually overshadows any description of what really happens at the time of a solstice.

The image shows light and dark across the earth at the time of the solstice, which is June 21 at 05:45 UTC (also known as Zulu and Greenwhich Mean Time and Zulu time). This is 1:45 a.m. U.S. eastern time, 12:45 a.m. central time, 11:45 p.m. on June 20 mountain time, and 10:45 p.m. June 20 Pacific time.

At this time, the sun will be directly above the Tropic of Cancer (23.4 degrees north latitude) and 94.2 degrees east longitude, which is in eastern Burma not far from the border with Bangladesh.

The Tropic of Cancer is the farthest north where the sun is ever directly overhead. Chapter 2 of the AMS Weather Book explains all of this with the help of graphics, including some like the one above and also for the equinoxes and the winter solstice.

By the way, while at some places June 21 will be the “longest day of the year” by a minue or so, at many locations three or four  days that include the solstice will be equally long. You can look this up for any place in the world by going to the U.S. Naval Observatory’s Sunrise and Sunset Tables for each day of the year.

One Response to “Summer Begins Sunday! Really?”

  1. […] The question refers to an answer I published last June, “Summer begins Sunday! […]