Why Idaho Summer Days Are Getting Shorter & Why We Love It!

Idaho's famously long summer days are beginning to dwindle, and we're not losing sleep over it.

It's quite the opposite, actually. We're of the mind that earlier sunsets have a multitude of positive fringe benefits. Better or more restful sleep—especially if you have kids—cheaper utility bills, and not getting blinded behind the wheel driving westbound at 8:30 p.m. are just a few perks. But here's the deal: Why Idaho Summer Days Are Getting Shorter & Why We Love It!

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Basic Science Behind Sunsets

Sunsets are every-changing events. A sunset's timing is determined by a combination of where it's viewed from Earth as well as it's latitudinal and longitudinal measurements. Elevation also plays a significant role. Minor daily and semi-annual transitions throughout the year change in accordance with the Earth's axial tilt, rotation, and orbital movement along with the Earth's revolutions in concert with the moon's.

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Understanding Sunset Times

Long summer days north of the equator are the product of of Summer Solstice events; a time when the days become longer. The yearly event occurs between June 20th and 21st when the Earth's axis tilts toward the sun. Winter Solstice events yield shorter days as the Earth's axis tilts away from the sun.

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Earth-Sky Horizons & Celestial Horizons

We all know the Earth and sky are separated by a theoretical plane known as the horizon. But did you know there are two different kinds of horizons?

An Earth-sky horizon is the exact point where the sky meets the Earth's surface over land or sea. Quite often this visible line where the sky meets the Earth is obstructed by mountains, trees, and buildings. A seaside view of the horizon is called an offing.

As measured by astronomists, celestial horizons determine the Earth's position and distance relative to the sky.

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Disappearing Act

Sunset, also known as sundown, is the sun's daily disappearance below the horizon spurred by Earth's rotation. From the vantage point of the equator, spring and autumn sunsets occur due west. As viewed from the middle latitudes, summer suns set in the northwest for the Northern Hemisphere and Southwest for the Southern Hemisphere.

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Twilight

Twilight is divided into three distinct stages: civil twilight, nautical twilight, and astronomical twilight. Civil twilight occurs after the sun disappears below the horizon. It lasts until it's six degrees below horizon. Nautical twilight occurs between six and 12 degrees below the horizon. Astronomical twilight occurs between 12 and 18 degrees below the horizon.

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Dusk & Nightfall

The darkest period of twilight, dusk occurs at the conclusion of astronomical twilight just before nightfall. Finally, true nightfall occurs when the sun falls 18 degrees below the horizon and ceases to illuminate the sky.

Interested in more to-do's about the ways of the sun? Check out our galleries on Idaho's standing in the Daylight Savings debate.

We Can All Agree Boise Is Not Supposed To Be In Mountain Time, Right?

Let's take a close look at the Time Zone Map here in the US to try to understand it better. Right now, I have no idea why Western Idaho is still in Mountain Time. If you live here and are wondering why it's still dark outside at 10pm, then you feel me.

Let's see what we can learn from the map.

Gallery Credit: Cort Freeman