How long is a season?

[rowan46]

1st day of Spring 21st march. midsummers day 22nd june so how long are spring and summer?

[Cath]

Depends who you ask, but the general dates are ..

21st Mar ... Start of Spring

21st Jun ... Start of Summer

23rd Sep ... Start of Autumn

21st Dec ... Start of Winter

[rowan46]

so why is the start of summer on midsummers day?

[Cath]

"Who ever said the human race was logical"

[Cath]

The hottest months in the UK tend to be July and August, so I guess the surface temperature throughout the year tends to lag behind the suns exposure times? .. only a guess Rowan.

[rowan46]

Sorry if I sound grumpy just attempted my first observing session since sgl7 and found someone has built the Blackpool illuminations right next to my spot a bit miffed no back garden and now no observing spot within 6 miles and no car. So I thought I would ask stupid questions on here just to relieve the frustration sorry.

[David JM]

so why is the start of summer on midsummers day?

It's not. "Midsummers Day" is actually the Summer Solstice, the longest day of the year. If 'summer' counts as the warm months and 'winter' the cold then summer is June/July/August and winter December/January/February. Of course this year went Jan/Feb winter, March summer, April/early May winter, mid May spring.

Anyone like to have a guess at which bank holiday are most likely to see snow?

[David JM]

Sorry if I sound grumpy just attempted my first observing session since sgl7 and found someone has built the Blackpool illuminations right next to my spot a bit miffed no back garden and now no observing spot within 6 miles and no car. So I thought I would ask stupid questions on here just to relieve the frustration sorry.

Why apologise, it's a perfectly valid question.<text removed>

[pete_l]

Depends who you ask, but the general dates are ..

21st Mar ... Start of Spring

21st Jun ... Start of Summer

23rd Sep ... Start of Autumn

21st Dec ... Start of Winter

Yes, those dates are the answer to the exam question. But like a lot of things that we all get taught, it doesn't really match up with reality. Especially as in England, it's possible to have any season's weather in any month

The Met Office has adopted the "common sense" approach that most people regard as more realistic:

March, April, May = Spring

June, July, August = Summer

September, October, November = Autumn

December, January, February = Winter

So although they may not be the "official" (although there is no recognised body to set such things) dates - and it's merely convention that the seasons are all the same length anyway - starting spring on March 1 is much tidier.

[Darkstar_1]

The reason the summer solstice is called midsummers day is because originally (in celtic times) there was only 2 seasons, summer and winter. Summer was from the spring equinox to the autumn equinox and winter from the autumn equinox to the spring equinox. Also explains why winter solstice is called mid winter.

clear skies, Den.

[Qualia]

This is a great question and very difficult to truly answer.

Relative to our distance from the Sun, Earth's Perihelion occurs in January and its Apehlion is in July. So, Earth is nearer the sun in the Winter and further away in the Summer.

However, due to the Earth's tilt relative to the perpendicular on the plane of its orbit around the Sun (currently at about 23.4º), our seasons will change depending on where that tilt is leaning.

So, although further away from the Sun in July, in the Northern hemisphere we are tilting more towards the Sun. So around this month will be our summer time.

Spring and Autumn are not favoured, for they will receive equal amounts of light and night, moving towards more light in the Summer and less light in the Winter.

Earth's tilt varies between 22.1º to 24.5º and takes about 41,000 years to rotate from the minimum to maximum angle. A fancy word for this tilt is Obliquity and it is believed that Obliquity has massive long term affects on Earth's climate. The entire class of huge climate changes such as the ice-age belong to the Milankovich Cycles.

Apart from Obliquity, we must also take into account Earth's Precession. We can imagine Earth's tilt (its obliquity) working through its 2º angle over 40,000 odd years and as it is doing this, it is wobbling a little. This is Earth's precession and takes about 26,000 years to work through its own loop.

With precession, by the time you have moved around the Sun a few thousand times, for argument's sake, we can imagine the tilt of Obliquity remaining very much the same, but the wobble of Precession means the Earth is not pointing in exactly the same direction.

So, although our angle of tilt remains at 23.4º, for example, we've wobbled a little away from the Sun which means that our summer will now happen just a little before on our orbital plane.

Of course, these changes take 1000s of years, but strictly speaking, Precession changes our sense of seasons. Every year, due to this slight wobble inside the tilt of obliquity our seasons are occuring just a little earlier.

As we have seen, at the moment Earth is closest to the Sun in January and keeping in line with Kepler's second law of planetary motion, Earth sweeps through that part of its elliptic orbit fastest.

The upshot being that northern winter (southern summer) is the shortest season, whilst northern summer (southern winter) will be the longest. Thus, they cannot be of equal measure.

As we have seen the Earth wobbles or twists on its tilting axis over a 26000 year period, so each year starts a little earlier in Earth's orbit than the one before.

So from zero (cover that with the celestial longitude below), it will take 26,000 years before the Sun and stars get back to the same apparent alignment at the start of zero.

Meanwhile, the closest point to the Sun in Earth's orbit drifts from year to year, and the shape of that eliptical shape of that orbit works through a cycle of about 100,000 years.

So, each year after the Earth has gone around the Sun, its orbit has drifted or changed just a little. The net result of obliquity, precession and eliptic drift means that winter and summer should be reversed every 10,000 years or so.

Adding to this confusion, we must take into account our coordinate system. The intersection of the celestial ecliptic with the celestial equator, will give the Equinox, occuring this year around March 20th and September 22nd.

The point on the ecliptic where the sun is most north or south of the celestial equator will give us the Soltices. This year we should experience them on the 20th June and 21st December respectively.

The time from equinox to equinox is called a tropical year. This year is different in length from a sidereal year. It is the tropical year which is used to prevent the seasons from flying through our calendars, so for us spring will never be in December.

Final point, the seasons for Earth lag. The hottest times usually occur a month or so after the time of maximum solar energy is deposited on earth.

So probably this year, our essential summer will probably be around the end of July, our chilly winter around January, and our Spring and Autumn.

My head hurts!!!!

[dtr42]

It's not. "Midsummers Day" is actually the Summer Solstice, the longest day of the year. If 'summer' counts as the warm months and 'winter' the cold then summer is June/July/August and winter December/January/February. Of course this year went Jan/Feb winter, March summer, April/early May winter, mid May spring.

Anyone like to have a guess at which bank holiday are most likely to see snow?

we had snow on the hills around glasgow on the may day monday but have seen snow on ben lomond in june and july [we had a snowball fight on my 42nd birthday at top of ben lomomd on the 20th june 6 years ago ]

[Jon Sales]

Seasons are supposed to be 3 months long for each but I find if I apply this rule it is much more accurate.

Spring - 21st March

Summer - 22nd Jun

Autumn - 1st August

Winter - 18th September

:)

[ismangil]

I find the seasons here in UK to be in general 6 hours long.

That's from empirical observation, that I can experience 4 seasons in a day!

On mobile (excuse the strange predictive words...)

[SFlowers]

I find the seasons here in UK to be in general 6 hours long.

That's from empirical observation, that I can experience 4 seasons in a day!

On mobile (excuse the strange predictive words...)

I think 6 hours is being generous

[Scott]

As an aussie now living i the uk i thought the seasons were:-

summer= 1 week randomly placed somewhere between march and may

winter= the other 51 weeks

please don't think i'm moaning, it was meant as a joke.

i actually think i love my new country more than a lot of natives i've met over the last 10 years.

[Polar Bear]

I find the seasons here in UK to be in general 6 hours long.

That's from empirical observation, that I can experience 4 seasons in a day!

On mobile (excuse the strange predictive words...)

Especially on a walk up Ben Nevis in the middle of August

Paul

[Mr Spock]

We had summer in March. We are now in autumn heading for winter

[Cath]

i actually think i love my new country more than a lot of natives i've met over the last 10 years.

I actually like our weather AusPom. It would be nice to have less cloud from time to time but I like the fact that we don't tend to get the extreme temperatures (hot and/or cold) etc that other parts of the world get.

[ismangil]

I must have liked the weather too, living here for the past 12 years...

Note I am an immigrant from Indonesia where the weather is either hot or very hot...

I suppose if I moan occasionally is the *unpredictability* rather than the actual temp or lack of sun.

On mobile (excuse the strange predictive words...)

[Double Kick Drum]

Yes, those dates are the answer to the exam question. But like a lot of things that we all get taught, it doesn't really match up with reality. Especially as in England, it's possible to have any season's weather in any month

The Met Office has adopted the "common sense" approach that most people regard as more realistic:

March, April, May = Spring

June, July, August = Summer

September, October, November = Autumn

December, January, February = Winter

So although they may not be the "official" (although there is no recognised body to set such things) dates - and it's merely convention that the seasons are all the same length anyway - starting spring on March 1 is much tidier.

Thanks for that. They are the dates I recognise. 1st March beginning of spring etc.

Thought I was going mad there for a moment!

[cotterless45]

Many years ago, we used to tell seasons by the weather.Winter was cold,spring warm and pleasant,summer was scorchio,autumn had a scent and colour of it's own.

Now when the butler wakes me up, looking out of the window ,I don't know what time of year it is.

[Scott]

I actually like our weather AusPom. It would be nice to have less cloud from time to time but I like the fact that we don't tend to get the extreme temperatures (hot and/or cold) etc that other parts of the world get.

Must admit i can't handle the aussie summers anymore. always make sure when we go back for a visit it's autumn or winter. until i started in astronomy i loved the English twilight, now i find myself longing for those early winter nights.

[sologuitarist61]

I find the seasons here in UK to be in general 6 hours long.

That's from empirical observation, that I can experience 4 seasons in a day!

On mobile (excuse the strange predictive words...)

Come to Cornwall, we can all of them in just one day

[Scott]

I got up yesterday- snowing. drove to manchester- raining. started work- sunshine. finished work- huge hail storm with thunder and lightening. got home, had tea, set up scope viewed til 1.00 am- beautiful clear skies. now thats a mixed bag for 1 day.haha