We Love Weather Exclusive

The 2016 Fall Equinox

Not every region in North America will experience 12 hours of daylight and 12 hours of darkness during the fall equinox. Wonder why? Winter Weather Expert Tom Niziol will fill you in.

Here is a great chart from Brian Brettschneider showing the date at which locations get equal daylight and darkness (12 hrs for both) in North America. Note however that this does not occur on the autumnal equinox everywhere. Why?? Well below are a couple reasons…

First, at equinox (September 22, 2016) it is the geometric center of the sun that’s above the horizon for 12 hours. But sunrise is defined as when the top of the sun first appears on the horizon and sunset when the top of the sun drops below the horizon. So at equinox, the total day lasts just a bit longer than 12 hours. A second issue we deal with is the refraction caused by our atmosphere. The atmosphere actually bends the light (refracts) a bit so that the top of the sun actually appears several minutes before it physically reaches the horizon and it hangs around a bit longer after the sun has actually dropped below the horizon at sunset. Hope this little lesson has “brightened” your day 🙂


Join the Discussion


  1. Thanks, Mr. Niziol

    I did not completely understand until you explained it in a simple way. I always thought the equinox was exactly on the day listed on the calendar.
    Now I know…


  2. thanks for explaining this in such a way anyone could understand! Love your show; keep up the great work folks!

  3. Thank you for this information! I love all you wonderful folks at the Weather Channel!!!

    1. I would suggest to continue to talk to them, call and ask for someone who will listen in their marketing dept. possibly. Let them know how much you miss Expert coverage of all sorts of weather across the US and how monitoring The Weather Channel not only entertains and educates but as we have shown so many times, it can actually save lives.

  4. l love the WEATHER CHANNEL and I am still very angry the WEATHER CHANNELwas dropped in the Baltimore/Annapolis area. I love when we travel; the first thing I do in my hotel room is turn on the TV and look for the weather channel. NO ONE give us storm information like the WEATHER CHANNEL. You can laugh but we truly miss tuning in.

  5. I always thought that latitude played a part in this too. I’m probably confusing equnox with length of day.
    Thanks for this neat lesson.

Comments are closed.