Spring - 1 September
Summer - 1 December
Autumn - 1 March
Winter - 1 June
Well, those are the official starting dates for the seasons but the weather makes its own arrangements.
See, I woulda labeled them as Livable, Dry Hot, Rainy Hot, and Chilly. Livable is Feb - late April; Dry Hot is from then until June-ish, when it turns to Rainy Hot until November, when it rolls over to Chilly until February.
The seasons in Havre, MT
[ul]
[li]At least it’s a dry 110: June-August, with occasional appearances in May and September.[/li][li]September showers bring sleet: September and October, with October building up a good blanket of snow. Maybe.[/li][li]Manic-depression is a snow-melting mess: November-February, marked by -40F to 60F and roads that turn from packed snow to slushy mud to glazed ice in the period of a few weeks. And where is our warm air coming from? Canada.[/li][li]Who’ll stop the rain?: March-May, when this place can go from brown and sterile to green and crawling with bugs. Around here, gumbo isn’t thick stew: It’s mud that strongly resembles thick stew. At least we don’t have palmetto bugs. We have mosquitoes instead.[/li][/ul]
Right now, in my part of California, Winter runs from the end of November until about May. There’s a brief “spring” period, which quickly turns into Summer. Summer lasts until late November. (It’s been a couple of years since I’ve seen a true autumn.)
I live in Norway. We do not speak of when the seasons begin and end here, because this may anger the Weather Gods, and the consequences could be quite dire indeed.
The seasons begin and end when it pleases the Weather Gods.
In the Caribbean, hot, hot, less rainy, and hot.
San Francisco’s “seasons”: (the western side, those of you in the east part of the city or the other side of the coastal hills might as well be on the moon)
Wet: Save up yer rain, you won’t get any more… storms plow in from time to time, interspersed with clear skies but chilly days… usually December to late January/February - but El Niño years can extend this much later (this past one lasted until May or so)
Windy: Earth is trying to blow you off the planet. Luckily the clouds are easier to blow away than you are. Clear weather, and it would be warm if it weren’t so windy. March through late May/early June.
The Fog: Having unsuccessfully tried to blow you off the face of the Earth, nature now tries to hide the Earth from you. Giant fog banks roll in to conceal various things from you: the Golden Gate Bridge, the Bay, your own extremities. Sometimes nature lifts the bank for a day (or if she’s real impatient, an afternoon) for a perfectly clear sunny day with a temperature in the 70s just to show you what you’re missing. She likes to taunt us. May/June through August.
Ha, You Thought Summer Couldn’t Start in September: Warm, clear days. Usually quite pretty. I can only assume nature has been distracted by some shiny object or possibly left her fogbank in the pocket of her other pants. September through October.
The Wheel of Fortune: Take a spin, you never know what you’re gonna get. Could start in with more winds, or be clear, or overcast. Storms could even start early if you spin wrong. Note: results of your spin are not binding Nature reserves the right to make you look like a silly git for dressing inappropriately for any type of weather. November/December.
Snow?
What is this thing called snow?
Ahh!
You mean that thing we eat with fruit syrup. 
You might have tried reading the OP instead of just the title.
Here in the Dominican Republic we have two seasons: verano * and infierno
*Summer and hell (a wordplay, winter is spelt invierno)
Non-technical descrpition for where I am:
Winter: Usually December through to mid-March. The temperature ranges between 8 and 23 degrees C. No snow or rain.
Summer: Mid-March through to mid-June. Temperature ranges from low 30s to mid 40s. Occasional summer showers cool things down temporarily, but they’re not frequent. Humidity crosses 90%
Monsoon: Mid-June through to the end of August. Plenty rain, temperature ranging between 15 and 25 C. My favourite time of the year.
Summer (again!): September and October. Hot and humid.
Pre-winter: November. The temperature goes down a bit, but it’s not cool as yet. Humidity reduces, so it’s not very uncomfortable.
This is Poona, about 100 miles south-east of Bombay, but a whole world away weather-wise.
Ah yes, San Francisco. We in the East Bay have rather different weather, despite being only a bridge away. I’d like to thank you for blocking most of that fog, it gets rather inconvenient. However, I don’t understand why we get high winds over here in October if you get them earlier in the year.
Heh, quite right for you southerners 
But I live in the middle of Norway, and in this part of the country the Weather gods are constantly either blind drunk or bakfull, so it doesn’t matter what we say *). There are several schools of thought regarding the seasons. Some of the most popular:[ul][li]Vivaldi wrote The four seasons after two days in the middle of Norway. He needed the second day to make sure that he hadn’t hallucinated the first day.[/li][li]There are two seasons: Green winter from May through September, and White winter from November through April. [/li][li]There are four seasons: [/li]- Spring in April and May
- Summer(ish) in June through August
- Autumn in September through March
Winter may occur at any time during autumn except the first month, and may last from a single day up to several weeks. There are usually somewhere between half a dozen and a dozen winters every year. (According to Norse myths, the Vikings believed that the world ends after a period with seven winters without any summers between. Wimps, I call 'em.)[/ul]
*) Every rule has an exception: Don’t ever say the g-word, unless you’re really eager for a huge downpour. Don’t even write it. (The Norwegian word for “barbeque” begins with a “g”.)
hildea, your mention of the various “winters” makes me curious if other locales have things similar to the ones in this area. There’s:
Indian Summer (in the fall after it’s begun getting cooler, with perhaps a frost or even a snow, that lasts anywhere from a day or two to a couple of weeks) when it’s warm enough for short sleeves or even shirtless for most hours of the day.
Blackberry Winter
Locust Winter
other “winters” that I forget the names for but all coming well into Spring after trees have begun to leaf out (at least to bud) and which can bring freezing temps to kill off early growth, named for whichever trees (or other vegetation) start budding or blooming at that time.
Also, do any of you look forward to “the nip” which is the harbinger of football season and which amounts to a dry warmth instead of the muggy heat of late summer, with clear blue skies, light breezes, and a sweetness to the air? The sort of days and nights that are perfect for fires and weiner roasts and s’mores and marshmallows and ghost stories, when the front of you gets hot while your back gets cold. I wouldn’t be overly surprised if “the nip” is just weeks away.
We get high winds in October too. I only really mentioned winds when we get high high winds. 
Nice, wevets.
It really is weird to drive across the Golden Gate Bridge, and not be able to see it… something I’ve experienced each of the last two weekends.
And I love it!
People here in Japan say they have four clearly divided seasons, and I would have to agree - although I would like to add a fifth, sub-season:
Winter : December - February (5 - 15 degrees)
Spring : March - May (10 - 25 degrees)
Rainy Season : June (15 - 30 degrees + rain)
Summer : July - September (30 - 35 degrees + humidity)
Fall : October - November (15-25 degrees)
Sometimes, the season change is strangely rapid. You can feel the humidity and temperature dropping drastically over a weekend, marking the transition from summer to fall…
How’s the weather in Washington, DC in September? I’m going on a trip there with available light and her family.
Here in Melbourne, Australia, the seasons are officially gazetted as:
Spring: 1 Sept to 30 Nov
Summer: 1 Dec to 28 Feb
Autumn: 1 March to 30 May
Winter: 1 June to 31 Aug.
However, mostly we get Spring weather from maybe mid-October right through until January, when it finally gets hot enough to don the swimming togs and bring out the esky and the barbie. And the ‘hot’ weather now seems to last until well into April or even May, although the nights do seem to get chillier, as they should, according to the Gazette.
June and July seem to be the more autumnal months now (my Japanese Maple didn’t start losing its leaves until around the 15th of July this year), whilst August and September are the truly freezin’ freakin’ cold times.
Just for your information, some areas of Melbourne metro got bloody snowed on today. :eek: That is almost unheard of in this part of the world, with the last white stuff falling around 30 odd years ago I believe.
It was so cold that there were some Fairy penguins washed up on a suburban beach with a bad case of hypothermia*.
*I’m serious.
Well, here in Chicago, road construction starts generally the beginning of April and lasts through the end of October or into November a bit. Then there’s winter.