Farmers Almanac
The Farmers Almanac
Now Shipping!
The 2019 Almanac! Order Today

The Sun Playing Tricks? Blame It On The Atmosphere

Share on Facebook Share on Twitter Add to Google+ Share on Pinterest Share on LinkedIn Subscribe by Email Print This Post
The Sun Playing Tricks? Blame It On The Atmosphere

On Saturday, March 17th – St. Patrick’s Day — for many locations across the United States, the length of day and night will be equal. For New York City, for instance, the Sun will be above the horizon for exactly 12 hours, rising at 7:05 a.m. and setting at 7:05 p.m. But wait! How can this be? The date we commonly associate with equal days and equal nights is the vernal equinox, which doesn’t occur until the following Tuesday, March 20th, when the Sun will stand directly over the equator at 12:15 p.m. Eastern Time. On that day, the length of daylight will be 12 hours and 8 minutes long. So, why the apparent discrepancy and what’s the explanation? Blame it on something called “atmospheric refraction.”

How Atmospheric Refraction Affects Sunrise and Sunset

First, sunrise and sunset are measured when the Sun’s uppermost rim first appears above or last disappears below the horizon. Our atmosphere also acts like a lens to bend or refract the Sun’s image above the horizon when it’s not really there. So when you see the rising or setting Sun sitting on the horizon, keep in mind that what you’re seeing is an illusion! In actuality, the Sun is still below the horizon. This effect, ends up lengthening the amount of daylight by about 6 to 8 minutes.

So thanks to atmospheric refraction we receive 12 hours of sunlight a few days before the date of the vernal equinox.

(Continued Below)

Articles you might also like...


There are no comments yet...

Kick things off by filling out the form below.

Leave a Comment

Note: Comments that further the discussion of the above content are likely to be approved. Those comments that are vague or are simply submitted in order to promote a product, service or web site, although not necessarily considered "spam," are generally not approved.

If you notice a hole in the upper left-hand corner of your Farmers' Almanac, don't return it to the store! That hole isn't a defect; it's a part of history. Starting with the first edition of the Farmers' Almanac in 1818, readers used to nail holes into the corners to hang it up in their homes, barns, and outhouses (to provide both reading material and toilet paper). In 1919, the Almanac's publishers began pre-drilling holes in the corners to make it even easier for readers to keep all of that invaluable information (and paper) handy.

Spring Is Here – Sign Up Today!

The Farmers' Almanac is a gardener's best friend. Get 365 days of access to our online weather and gardening calendars + a copy of the 2017 Almanac
for only $13.99 $11.99!

Subscribe Today »