We have just had the earliest sunset of the year, on December 7.

[mahatmakanejeeves]

If you live in the northern hemisphere, the sunsets will be occurring later each day from now until June. The day on which the earliest sunset occurs is not the day with the least amount of sunlight. It is also not the day on which the latest sunrise occurs.

Earliest sunset at 40 degrees N. latitude on December 7

The exact date for the earliest sunset or earliest sunrise varies by latitude. Toward the end of the first week of December, mid-temperate latitudes in the Northern Hemisphere have their earliest sunsets. The earliest sunset for 40 degrees N. latitude is on December 7. That would be the latitude of New York City (shown in Jerry Ferguson‘s photo, top of post); Philadelphia, Pennsylvania ; Kansas City, Missouri; Reno, Nevada; Beijing, China; Madrid, Spain; Naples, Italy. Meanwhile, the Southern Hemisphere’s mid-temperate latitudes are waking up to their earliest sunrises.
....

It seems paradoxical. At middle latitudes in the U.S. – and throughout the Northern Hemisphere – the earliest sunsets of the year come about two weeks before the solstice and the shortest day of the year.

Why isn't the earliest sunset on the year’s shortest day? It's because of the discrepancy between the clock and the sun. A clock ticks off exactly 24 hours from one noon to the next. But an actual day - as measured by the spin of the Earth, from what is called one “solar noon” to the next - rarely equals 24 hours exactly.

Solar noon is also called simply midday. It refers to that instant when the sun reaches its highest point for the day. In the month of December, the time period from one solar noon to the next is actually half a minute longer than 24 hours. On December 7, the sun reaches its noontime position at 11:52 a.m. local standard time. Two weeks later - on the winter solstice - the sun will reach its noontime position around 11:59 a.m. That's 7 minutes later than on December 7. ... The later clock time for solar noon also means a later clock time for sunrise and sunset.

Sunrise and Sunset, Washington, DC

You can look at the times for any month you choose.

I just missed seeing the moonrise yesterday. I don't get the paper anymore, so I had to guess when it would happen. I went inside to find a radio, and by the time I got back outside, the moon was already up.

Bonus link: Why doesn't the earliest sunset occur on the shortest day of the year?

Bonus bonus link: Equation of time

[BarbaRosa]

1. I've been following this for years now.

Here is another great source for all that kind of information.

http://aa.usno.navy.mil/data/index.php

The second down is a spreadsheet with local data. According to the chart Friday is when we in SW NM will have gained a minute of sunlight in the evening. We're still losing daylight in the morning, and will do so until mid January.

Neat stuff!

[John1956PA]

2. Thanks for this information.

As I understand it, as the earth speeds up as it moves around the perigee, or "tight arc" of its elliptical orbit. It seem to me that the earth's rotational time to get back to "noon" would be influenced because of the tightness of the arc and because of the earth's faster speed through the perigee. However, it is my understanding that the earth's tilt is not aligned with the perigee of the ellipse and that the perigee point is in January, rather than in December. I look forward to reading the links to clarify this in my mind.

[elleng]

3. THANK GOODNESS!

I got a picture of it, in Silver Spring: