Winter Solstice and Sunrise

Forums: Astronomy, Nyc, Winter Solstice, Sunrise, Daylight
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I believe the Winter solstice occurred about December 21st (I am in New York City). I believe that the duration of sunlight increases after the Winter solstice.

However in New York the time of sunrise was:

January 4 - 7:20 am
January 5 - 7:21 am

Why is sunrise getting later?

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@gollum,

not sure where you got that info, but this page says the sun will rise in NY @ 7:20am through 1/10/12...

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@gollum,

One thing I have noticed is that as the length of day changes, time sunrise does not change by the same amount as the time of sunset. I have never quite figured that one out. Also, the amount of change per day is very slight at solstice, and very rapid at equinox.

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@Region Philbis,

That's a great site, Region. Thnx for the link.

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@Region Philbis,

Thank you.

My source is The New York Times. I guess the Gray Lady is wrong.

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@gollum,

gollum wrote:

I believe the Winter solstice occurred about December 21st (I am in New York City). I believe that the duration of sunlight increases after the Winter solstice.

However in New York the time of sunrise was:

January 4 - 7:20 am
January 5 - 7:21 am

Why is sunrise getting later?

I think you're probably looking at "rounding errors" or "rounding skew". It's unlikely that the sun rises on exactly even minute intervals, so there are obviously seconds involved.

After the solstice, it's the total daylight which increases, not necessarily the sunrise time. And I think because we're in the northern hemisphere it's the sunset time which deepens more than the sunrise recedes (but I'm not certain of that).

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@roger,

roger wrote:

One thing I have noticed is that as the length of day changes, time sunrise does not change by the same amount as the time of sunset. I have never quite figured that one out. Also, the amount of change per day is very slight at solstice, and very rapid at equinox.

I think it's because we're in the northern hemisphere. The solar "noon" just gets deeper and deeper into the day. I'm having trouble explaining this.

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@rosborne979,

The differences you're seeing in northern hemisphere are due to the earth's tilt. The opposite effect occurs in the southern hemisphere.

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The solstice does not coincide with latest sunrise or earliest sunset anywhere but at the equator. The amount of difference is determined by your latitude. In Chicago latest sunset occurs around Dec 11 and earliest sunrise occurs around Jan 8th. The solstice represents the shortest day defined by the length of daylight hours but sunset has already turned by then and sunrise is still getting earlier.

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Winter Solstice and Sunrise

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