Date Sunrise Sunset Day Length
December 21 7:16 AM 4:32 PM 9h 15m 18s
March 21 6:56 AM 7:09 PM 12h 13m 32s
June 21 5:25 AM 8:30 PM 15h 5m 45s
September 21 6:56 AM 7:09 PM 12h 13m 32s

 

Sunrise - sunset - day length - civil twilight - astronomical twilight

 

Q: Why is there more than 12 hours of daylight on the equinox?

A: On these two days, the geometric center of the sun is above the horizon for 12 hours, and one might think this would indicate that the length of the day (hours of daylight) would be the same.

However, ‘sunrise’ is defined as the instant when the upper edge of the sun's disk becomes visible above the horizon – not when the center of the sun is visible. In the same sense, ‘sunset’ refers to the moment the upper edge disappears below the horizon. At both instances, the center of the sun is below the horizon, and therefore the equinox day lasts a little longer than 12 hours.