Equinox in Latin way equal night, giving the impression the the night and day top top the equinox are exactly 12 hours long. And also even despite this is usual wisdom, it isn"t completely accurate.

You are watching: Equal day and night of the year


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The job is just a bit longer than the night on one equinox.

The day and also night are only nearly equal ~ above the September equinox and the in march equinox. In fact, most areas on planet tend to enjoy much more daylight hrs than nighttime hrs on these 2 days of the year, many thanks to the Earth"s atmosphere and our definition of sunrise and sunset.

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More than 12 hours of Sun

The next equinox is at 15:33 UTC on in march 20, 2022. ~ above this day, brand-new York City inhabitants will enjoy a 12 hour and 8 minutes lengthy day. Those in Amsterdam will get 2 more minutes the daylight v a 12 hours and 10 minutes long day. Also in Longyearbyen, one of the world"s northernmost cities, the day will certainly last because that 12 hours and 29 minutes.

Moving southwards, Melbourne in Australia will check out a 12 hours and 9 minutes long day. Johannesburg citizens will additionally enjoy a similar variety of daylight hours.

On the south Pole, the sunlight will be up 24 hours. Perfect chance to check out the Midnight Sun!

On the equator, the work is always a small longer than 12 hrs all year round.

Earth: The living planet


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On the equinox, the tilt of earth’s axis is perpendicular to the Sun’s rays as in the illustration.

Sun"s upper Edge defines Sunrise

One of the factors why most places on earth do no enjoy specifically 12 hours of daytime and 12 hours of nighttime on the equinoxes is exactly how sunrise and sunset are defined.

If sunrise and sunset were identified as the minute the geometric facility of the sun passes the horizon, then the day and night would certainly be precisely 12 hrs long. Yet that is no the case. Sunrise and also Sunset are characterized as the precise moment the top edge that the Sun’s disk touch the eastern and the west horizon, respectively. The time it takes because that the sun to completely set, which have the right to be numerous minutes, makes the day just a little longer than the night top top the equinoxes.

The Sun: Our house star

Approx. Day of "Equal work & Night"

LatitudeMarchSeptember60° North55° North50° North45° North40° North35° North30° North25° North20° North15° North10° North5° NorthEquator5° South10° South15° South20° South25° South30° South35° South40° South45° South50° South55° South60° South
Mar 18Sep 25
Mar 17Sep 25
Mar 17Sep 25
Mar 17Sep 25
Mar 17Sep 26
Mar 16Sep 26
Mar 16Sep 27
Mar 15Sep 27
Mar 14Sep 28
Mar 12Sep 30
Mar 8Oct 4
Feb 24Oct 17
No equal day and also night
Apr 14Aug 29
Apr 1Sep 10
Mar 28Sep 14
Mar 26Sep 16
Mar 25Sep 17
Mar 24Sep 18
Mar 24Sep 19
Mar 23Sep 19
Mar 23Sep 19
Mar 23Sep 20
Mar 23Sep 20
Mar 22Sep 20

Refraction: irradiate Lingers

Another factor for why the work is much longer than 12 hours on an equinox is due to the fact that the Earth"s environment refracts sunlight.

This refraction, or bending of the light, reasons the Sun’s upper edge to be clearly shows from planet several minutes before the edge actually reaches the horizon. The same thing happens at sunset when you can see the sunlight for number of minutes after ~ it has dipped under the horizon. This reasons every work on Earth, consisting of the work of the equinoxes, to it is in at least 6 minutes longer than it would have been there is no this refraction.

The degree of refraction counts on atmospheric pressure and temperature. Ours calculations in the Sunrise and also Sunset Calculator assume the conventional atmospheric pressure of 101.325 kPa and temperature the 15° C or 59° F.

Latitude identify Day Length

Even if day and night aren’t precisely equal ~ above the job of the equinox, there space days when sunlight hours and also nighttime hours are both very close to 12 hours. Now is recognized as the equilux, and also its date depends ~ above a location’s latitude and can occur several days to weeks before or ~ an equinox.

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Sunrise & sunset times

The table mirrors approximate days for as soon as day and also night space of similar lengths for part latitudes.