Does this column of Cecil’s mean that, even thogh we keep hearing today is “the first day of winter”, there is no “offcial” first day of (any season) in the US? Cecil seems to imply the meteorology service uses 3-month blocks, hence:
June July August = Summer
and presumably,
September October November = Fall
December January February = Winter
March April May = Spring
That would imply that, as far as any US government entity is concerned, which seems not to be very far, the “first day of winter” was 19 days ago.
I have a US government calendar at my desk, and it doesn’t show a “first day”, although it generally only shows government holidays.
I also rely on RSSchen’s fridge to mark the seasons. I believe that everyone does.
When Schen’s locked the door, the US Naval Observatory provides pretty good backup numbers:
The 2005 winter solstice occurs at 18:35 universal time.
Dec 21st is the date on which the Sun (for Northern Hemisphere folks) will set at its most southerly location. After Dec 21st, the Sun starts setting progressively northward.
The government does a lot of things, but I don’t believe it has ever felt the need to tell us when winter begins. Astronomers define winter as running from the winter solstice to the vernal equinox; meterologists (in my climate at least) as December 1 to February 28/29. Take your pick.
I have to disagree with Cecil here ( :eek: looks around nervously).
“There is a widespread misconception in this country–which extends, I might note, to the makers of most calendars, dictionaries, and encyclopedias–that summer “officially” starts on the day of the summer solstice, June 21 or 22, which is the longest day of the year. Americans also believe (1) that there is some valid scientific reason for doing it that way,”
He seems to be saying the right way (the “scientifically valid” way?) to determine seasons is temperature. I don’t see why that’s more valid then going by whether the days are getting shorter, or short and getting longer, etc. Obviously whether it “feels” like winter or summer will vary from place to place, even year to year, even if there are general patterens. The astronomical definition is at least completely consistent (errr…within a day or two every year that is).
I guess he’s saying the government hasn’t made any official determination (bit out of their jurisdiction I would think ) but going by the calanders we’ve agreed on the soltices and the equinoxs and I have to say that makes the most sense to me. (Darkness and light being as much a part of how we think about the seasons as temperature, surely.)
The solstices and equinoxes are astronomical events that relate to the great circles in the sky known as the Celestial Equator and the Ecliptic. The Ecliptic is the apparent path the sun makes through the sky in a year’s time. The Celestial Equator is the extension of the Earth’s equator and is based on the axis of rotation of the Earth.
The seasons are more meteorological than astronomical and have more to do with the residual effects of sunlight heating the atmosphere or the cooling effects when the sunlight is weaker.
The “events” determined by the sun’s position relative to the Celestial Equator are precise moments in time that vary year to year by a few days in each case so that the 20-23 dates in March, June, September and December are roughly when those events will occur. Similar considerations apply to Full Moon (and the other lunar phases), Eclipses and even the time of day when reckoned against the stars. Depending on one’s time zone those events can vary over a day’s (24-hour period) time. This may help to explain how such a precise moment can vary by time zone.
It is more a matter of convention that the periods between those events are referred to as Spring, Summer, Autumn (or Fall) and Winter.
The Southern Hemisphere will refer to these seasons in reverse order. For example, March 20-23 brings the beginning of Autumn in the Southern Hemisphere, since the apparent path of the sun is moving from its maximum height in the sky around December 20-23 (Summer) toward its lowest point in the sky in June, and has just crossed over the Celestial Equator – at the Equinox – when the lengths of day and night are roughly the same.
Good Lord. Cecil already did an article on why summer is screwed up in Ireland. Don’t tell me winter is screwed up too. He will have to write that up as well.
At least spring and fall are Ok (I presume). Other countries have a working calendar that you can borrow if you need to.
Apparently not the people at my office, who were calling today the first day of winter.
Astronomers mark the solstices, but do they care about/talk about “seasons”?
Is it safe to say meteorologists apparently go by the 3-month seasons described in my OP, largely since temperature/weather approximately conform?
What do we mean by “official” first day of winter? Who officiates?
I get the feeling that bored news reporters and calendar makers looking for something to print are the only reason we have an “official” claim to a “first day”. But I stand ready to learn otherwise.
Try this for fun; When the subject comes up, tell someone that Dec 21 is indeed the shortest day of the year - 23 hours long. June 21st is 25 hours long, so it averages out OK to 24 over the year. Let us know how many people you get to believe this.
“He’s as honest as the day is long…which means he’s least honest on December 21st” (I forget who said it.)
Okay… going by day length rather than temperature makes sense to me, however, I don’t really see the point in dividing the year into four ‘seasons’ based on:
Long-ish days and getting longer (spring)
Long-ish days and getting shorter (summer)
Short-ish days and getting shorter (autumn)
Short-ish days and getting longer (winter)
Mostly, because ‘getting longer’ and ‘getting shorter’ doesn’t seem quite so important, in this schema, as how long or short the days are, and the length of the days varies quite a bit between the equinox and the solstice. I would say that on this basis, it seems more useful to offset the seasons like so:
Very long days (summer)
Middling days, getting shorter (autumn)
Very short days (winter)
Middling days, getting longer (spring)
This would put the start of winter at about 5 november, and the end around 5 february, which would be a little off from our usual notion about winter temperatures, especially where I live, but you’ve thrown temperature considerations out of the window. It would cover the quarter of the year when the days were shortest.
This might be quite close to the irish system, I dunno.
I agree. Especially when you think of “Midsummer” meaning something like “the hottest day” and not just the longest. June 20 is rarely as hot (in these parts) as July and August days.
The period from the solstice to the equinox is called “astronomical winter”, not because astronomers have a particular fetish for or concern with seasons, but because it uses astronomical events as its endpoints.
Yes. This is called “meteorological winter”, and in most places in North America, it runs from Dec 1 through Feb 28/29.
Note that, in most places, this won’t correspond exactly to the coldest quarter of the year. According to Tom Skilling, the coldest quarter-year in Chicago runs from about December 10 through March 10. So both definitions miss it by about ten days.
I have no idea what makes you think one definition must be more “official” than another. I dare say that if you stop most people on the street and ask, “When is the first day of winter?”, you’ll get 12/21 more often than 12/1. (You’ll probably get “I don’t know” more often than either.) On the other hand, if you stop people today (12/20) and ask, “What season is this?”, most will probably say winter, because it’s cold and dark and it sure doesn’t feel like autumn. So there you have it.
Here is my understanding of the situationl. In North America, at least, maybe but not necessarily in other places, we somewhat arbitrarily call the three month period (approximately) between the winter solstice and the vernal equinox “winter”. While there is no actual scientific reason to do so. So tomorrow will be first day of winter in all North America. Note however, that if you should happen to live on Chatham Island, your solstice will occur at 8:20 AM on Dec. 22. And all of Australia, Siberia and points east will also have their solstices on the 22nd too.
When I was growing up back in the 60s, summer started on the day school let out somewhere around the beginning of June and ended when school started around the beginning of Sept. We didn’t care about exactly when the rest of the seasons started.
Sometime in the 70s (I think) TV weathermen started to say that the soltices and equinoxes were the “offical” start of the seasons. Where they got the idea that these were official, I don’t know. At a guess, from some popular almanac.
But note that such almanacs are not written by or for astronomers and so astronomers are not likely the source of this idea. This is something that a historian might want to hunt down, much like they found out where the idea of blue moon = second moon in a month came from.
Tomorrow is, of course, the winter solstice, the point at which the Sun marks its southernmost point, over the Tropic of Capricorn, and hence the longest day of the year south of the Equator and the shortest day of the year north of it.
The custom, at least in America, is to figure the seasons as running from each solstice or equinox until the next equinox or solstice (always from one to the other), producing this result for the Northern Hemisphere:
Dec-Mar: Winter. Days shorter than nights, but lengthening.
Mar-Jun: Spring. Nights shorter than days, but days still lengthening.
Jun-Sept: Summer. Nights shorter than days, but days becoming shorter.
Sept-Dec: Autumn. Days shorter than nights, continuing to shorten.
For the Southern Hemisphere, transpose the months list down or up two levels, keeping everything else the same.
In point of fact, the weather associated with the seasons varies locally, and might therefore lead to seasons not matching the equinoxes and solstices. AFAIK, no season-dating system is “official” anywhere.
) but going by the calanders we’ve agreed on the soltices and the equinoxs and I have to say that makes the most sense to me. (Darkness and light being as much a part of how we think about the seasons as temperature, surely.)