So on Saturday September 23rd at 04:03 a.m. (or Friday night at 9:03 p.m. for me in the Pacific time zone) the Sun will cross from the northern celestial hemisphere to the southern one, and most people will say it’s the start of autumn in the northern hemisphere.
I don’t say that, I say it’s the middle of autumn. But I have to explain this four times every fracking year, so instead of saying it again I’ll just point you to the blog entry I wrote in the spring about seasons and equinoxes and eggs.
Tip o’ the artist’s beret to BABloggee Steve Kluge for the great diagram!
September 22nd, 2006 at 5:10 pm
The sun does revolve around the Earth. Awesome!
September 22nd, 2006 at 5:22 pm
Personally, I would call the climate around the end of september the middle of Auttum. The seasons, meaning the yearly climate cycle, actually lags a bit because of the huge amount of water on the surface of this planet. Or something like that. Although it is a tad bit nippy for late september this year.
September 22nd, 2006 at 5:38 pm
Why on Earth do we use the astronomical season definitions (solstice to equinox and back) instead of the meteorological ones? Meteorological summer: June, July, and August. Meteorological autumn: September, October, November. (Winter and spring follow logically.) Makes a heck of a lot more sense to me.
September 22nd, 2006 at 5:51 pm
Because Brad J. Where I live November is well into winter. And on the equator there is no winter.
So what part of earth do you pick to define the “meteorlogical seasons”? I estimate we get 7-9 months of winter here, and somewhere between 2 weeks and 4 months of summer (depending on the year. This year it was hot all “summer” and part of spring, but last year it was cold and rainy the whole time). Spring and fall are only the times in between winter and summer here. Although last year we didn’t have a summer, so I guess you could say that we had Winter, then spring, the fall, then winter:P.
As you can see from my convuluted ramblings, it isn’t easy to define seasons.
September 22nd, 2006 at 5:51 pm
Autumn is starting?!! Someone needs to tell the thermometer! Wait - we haven’t had autumn in 10 years . . . Never Mind! I forgot we outlawed Autumn in favor of Tourism.
Just saying Hey!! from hot ‘n’ humid San Antonio, land of the two seasons: Hot and Really Hot.
jbs
September 22nd, 2006 at 6:00 pm
Going BAck to the Ptolemeic system, are we?
- Jack
September 22nd, 2006 at 7:49 pm
Of course it’s the middle of autumn, doh. Actually, I never really thought about it before but as soon as I read that sentence, I realized it was exactly right.
September 22nd, 2006 at 8:46 pm
Come on! Naming the seasons should be as simple as defining planets. Um… er… nevermind!
September 22nd, 2006 at 9:48 pm
I live at the North 61st latitude, and I’m headed into the long cold dark (again), and I can tell you that the tourists go home (mostly) by August 31. It gets a little chilly for them in December
September 23rd, 2006 at 12:50 am
In Southern California, September and October tend to be hot and dry, however short the sunlight may be. But then, most of the tourists are gone, so perhaps it’s fall after all.
It’s hard to agree that Lammas (August 1 or so) is actually the end of summer, when here the heat is typically peaking, or that Beltane (May Day, gray and cloudy) is its start.
The various harvests used to dictate our activities, and may still. The weather certainly does. If I depended upon a photovoltaic array harvesting photons I’d wholly endorse BA’s notion of seasons.
September 23rd, 2006 at 1:36 am
First day of autumn???? Maybe where YOU are!!! It was 98 degrees F (37 C) here (central Texas) yesterday!!!
September 23rd, 2006 at 4:23 am
Phil, I think it’s important to stress that although it is astronomically the middle of autumn, it is perfectly valid to use an alternative definition for everyday purposes because the actual weather lags the movement of the planet by a month or so.
Here in England it is frequently cold and icy at the start of March, and now at the end of Septemeber it is baking hot and people are swimming in the sea (as is usual).
September 23rd, 2006 at 6:01 am
It’s Springtime in Germany
September 23rd, 2006 at 9:44 am
…winter for Poland and France!
But seriously, equinox or not, forbye some rather windy and wet weather this week, autumn has hardly started here: trees are still green, it’s still warm etc etc. Perhaps with the advent of global warming we’ll have to start thinking about the seasons in an increasingly complex way…
September 23rd, 2006 at 10:43 am
“What’s an autumn?” -Renton Thurston
One thing my dad told me that I thought was interesting: Apparently if you’re on the arctic circle (or some other high latitude), the sun moves along the horizon on the equinox. We already knew it sort of looped in the sky during the summer, but we didn’t stop to consider the equinox.
September 23rd, 2006 at 8:16 pm
I agree with Phil. I am in New Zealand so our seasons are reversed and my fruit trees and shrubs have been in blossm now for over a month despite this having been one of the coldest winters on record. It’s obvious to me this is the middle of spring in the southern hemishere (autumn (fall) in the northern hemishere) and not the beginning of the season.
September 24th, 2006 at 11:53 am
I, for the first time I believe, don’t agree with Phil on this one. Here (northern Kansas) it is still late summer, with the first stirrings of fall. The idea that Fall started a month and a half ago here is just plain silly, we had several weeks of 100+ temperatures (the hottest part of the summer is August and early September here).
Nevermind the fact that “fall” and “spring” are not nearly 3 months long as far as the vegatation is concerned (more like a month or so)
Just keep the terms equinox and solstice astronomical, the meanings of season IS meterological and depends on your location and type of climate (north american contiental for me)
September 24th, 2006 at 3:48 pm
The sun does revolve around the Earth. Awesome!
That can’t be true. I’m sure I saw a thing that said the whole universe revolves around Paris Hilton.
September 24th, 2006 at 3:53 pm
Why on Earth do we use the astronomical season definitions (solstice to equinox and back) instead of the meteorological ones? Meteorological summer: June, July, and August. Meteorological autumn: September, October, November. (Winter and spring follow logically.) Makes a heck of a lot more sense to me.
Because that kind of a definition would vary greatly depending on where you are. Where I live, realistically, spring would be May; summer would be June-August, autumn would be September/October, and winter would be November-March… and that’s in a year when we actually get anything that could be called spring and don’t jump directly from winter to summer.
Ever since I was a child and learned about solstice and equinox, I’ve always wondered why we don’t start seasons 6 weeks before the solstice/equinox and end them 6 weeks after. That would match what humans have done historically and make a lot more sense meteorologically. Of course, I’m about the same age as BA, so maybe it’s some kind of idea born of being educated in the 70’s
The argument that the seaons would jiggle around on start and end dates is irrelevant because that happens now.
Just one of those things, I guess.
September 25th, 2006 at 1:47 am
Zamzara, what part of England are you in? In Surrey it is anything but hot! Woke to mist, overcast skies and it’s (hang on …) 17C outside right now.
We’re clearly half way through the harvest season. Tomatos all picked and gone, runner beans finished, Sunflower seeds almost ripe. Out in the fields around here the farmers have already cut and gathered their grain crops. Anyone who could consider now the start of Autumn either never goes outside or isn’t paying attention.
BA is right.
September 25th, 2006 at 9:32 am
I think at this point, yes, we’ve established that it is cold in Canada and hot in Texas. Here at the 47th paralell Autumn is right on schedule, the trees started leaving a month ago and it is about 55 degrees fahrenheit at the moment. I agree with Phil, though. The Summer and Winter solstices definitely mark the middle of their respective seasons.
September 25th, 2006 at 11:59 am
Here’s something that’s pestered me for a while: If Summer Solstice is when the Sun is at its highest in the sky, and Winter its lowest, then it would follow that the Equinoxes (Equini?) are midpoints. Does the Sun rise due east and set due west on those days? (That is, at the 90 and 270 degree points on the circle, instead of slightly more north or south.) If not, when might that happen?
September 25th, 2006 at 12:20 pm
I’m in Birmingham, England. Today’s temperature was in the mid 70’s and the leaves haven’t even started falling off the trees yet. Very unusual.
September 26th, 2006 at 9:45 am
Meteorologists use a simple definition for the seasons because the idea that seasons, both globally and locally, have fixed starting points down to the day in the year is unrealistic. Two or three weeks, sure, but not a day. It is pretty silly to be so specific about it. So meteorological seasons proper are used more for statistical “binning” of data than they are for explaining physical atmospheric and associated processes.
September 28th, 2006 at 5:42 am
I’m stunned to see so many Americans using “autumn” instead of “fall”! I had no idea the term was used in the U.S.A.
October 13th, 2006 at 9:50 pm
[…] Phil Plait, the Bad Astronomer pointed out when the Autumnal Equinox comes around, people call it the beginning of autumn, but he considers it to be in the middle of the season. The borders between seasons are fuzzy and vague, so for people who like fine lines in their lives, the point at which the day and night are equal in length (or technically, where the equator crosses the ecliptic) is a simple way to demarcate a seasonal transition. […]
September 21st, 2008 at 12:23 pm
HERE IN RIO DE JANEIRO, WE HAVE SUMMER AND WINTER ONLY [SPRING MIGHT BE A BETTER WORD] ALTHOUGH 40 DEGREE TYEMPERATURES IN WINTER ARE NOT AT ALL RARE. IN HTE TROPICS, THE TRADITIONAL SEASONS DO NOT MEAN MUYCH,AND THERE ARE REGIONS IN [NORTH] BRAZIL WHICH TRADITIONALLY CALL THE WET SEASON WINTER AND THE DRY, SUMMER, ALTHOUHG THE WET SEASON IS THE ATRONOMICAL SUMMER…
THE REASONS FOR THE SESONS ARE ASTRONOMICAL THOUGH, SO IT IS PERFECTLY VALID TO USE AN ASTRONOMICAL DEFINITION. ANYWAY, IT´S IMPOSSIBLE TO DEAL WITH TWO PARTS OF THE SAME COUNTRY WHICH ARE EITHER SIDE OF THE EQUATOR WITH EXACTLY THE SAME CLIMATE….