Where I live, the earliest sunset is sometime right around today, I believe (I might be off a day or two in either direction) - is there a term for such a day?
Thanks.
Winter solstice?
The winter solstice is the shortest day of the year - but the earliest sunset comes a couple of weeks before it, and the latest sunrise comes a couple of weeks after it (where I live, anyway - not sure if it works the same at all latitudes.)
According to this
Its round about dec 7th in the Northern Hemisphere.
Good question I hadn’t known/thought of that
And from the Guardian:
The reason is that a “solar day” – i.e. the time it takes for the sun to return to the meridian you happen to be on – is typically not quite 24 hours. It’s sometimes more and sometimes less. 24 hours is actually the length of a “mean solar day” or the average length of the solar day over a year. The length of a solar day can differ from 24 hours by as much as 16 and a half minutes. It varies due to effects caused by the tilt of the earth’s axis and the fact that the orbit of the earth around the sun is not perfectly circular (which causes the speed at which the earth orbits the sun to vary slightly through the year). When the solar day is shorter than 24 hours the position of the sun in the sky at “clock noon” edges gradually westwards day by day, when it’s longer than 24 hours it edges eastwards. Sunset and sunrise are symmetric around “solar noon” (the time the sun crosses your meridian), not clock noon.
Between around the beginning of September and Christmas Day the sun is already west of your meridian at clock noon so solar noon is earlier than clock noon (by around 3 minutes on 12th December). As the day is symmetrical around solar noon, less than half the day’s sunlight occurs after clock noon and more than half before. After Christmas Day (until mid-April) the sun is still east of your meridian by clock noon so solar noon is later than clock noon (again by around 3 minutes on the 31st December) and more than half the day’s sunlight occurs after clock noon and less than half before.
Close to the shortest day the actual length of daylight time varies very little so the effects of these changes in the difference between solar time and clock time become quite apparent in this asymmetry in sunrise and sunset times. The changing difference between solar time and clock time through the year is known as the “equation of time” and can sometimes be found on old sundials in the form of an “analemma” - a figure of eight etched on the face of the sundial which is used to correct the reading on the dial (solar time) to clock time.
Frank Roberts, London UK
Best to be careful about googling “analemma”, though. 
Didn’t she star with Ron Jeremy in the 70’s?
There is no common term for the day with the earliest sunset, other than “the day with the earliest sunset”. It varies with latitude, sliding closer to the solstice at higher latitudes. And of course there can be slight variation from year to year due to the cycle of leap years.
Let me emphasize this. The Dec 7 date someone cited upthread is for 40 degrees N. Where I live (46.5 degrees N) the day is the 10th.
Wow! The things you don’t learn till you’re 51! Can someone direct me to a site that does local sunset to the second? I can only find ones to the minute so I can’t figure out which day over the next few is the earliest. My google-fu is weak today.
Sunset and sunrise can’t be realistically computed to the second; the presence of trees and hills and such in your personal line of sight to the sun would dominate over the astronomical reality versus an assumed spherical Earth.
Minor correction: I’m actually at 45.5 N. The OP says today is the earliest at their location, so it’s obviously significantly further south than 40 N.
Fair enough. But folks upthread are identifying a day as the earliest sunset. When I go to the sunset chart for my area, I get a range of days all with the same hr:min. So how come they know a specific day and I just get a lousy, stinking week!
Here’s the handiest online tool I’ve found to determine it for your latitude: http://aa.usno.navy.mil/data/docs/RS_OneYear.php
I don’t think there’s a name for it… my own term of derision is “Seasonal Affective Armistice Day”. I can take the fact that the days keep getting shorter, but it just kills me when full-on twilight starts at 3:45 PM. Yes Alaskans, I know I’m a pussy.
In the case of my town, the earliest sunset runs consecutively for eight nights in a row from the 7th through the 14th.
Certainly, but “astronomical sunset” uses a theoretical horizon assuming no obstructions and average atmospheric refraction, and the time of that sunset can be calculated to the second.
If you take the middle of that week, you will probably have the correct day. At most you may be off by a day.
That’s only 8 days; for my location it gives no fewer than 12 days, centered on the 9th/10th.