Day and night not exactly 12 hours today - NBC12 - WWBT - Richmond, VA News On Your Side

Day and night not exactly 12 hours today

RICHMOND, VA (WWBT) - It's common knowledge that the First day of Autumn (and Spring) means that we have 12 hours and daylight and 12 hours of nighttime.  But that common piece of wisdom is wrong.

On the day of the equinox, the center of the sun is above the horizon for 12 hours.  But before the center of the sun rises, we get the benefit of a few minutes of sunlight as the first half of the sun's visible disk comes above the horizon. 

The same thing happens when the sun sets and we grab a precious few minutes of sunlight AFTER the center of the sun drops below the horizon.  On the Autumnal Equinox this year, we'll actually have 12 hours and 8 minutes of sunlight. 

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