please empty your brain below

Thanks for an interesting explanation of the winter gloom.
Only 3 weeks to the shortest day.
Very interesting. Max. elevation of 9.15 up here at 59deg North at 12pm today. No sunrise until around 8.35, and sunset at 15.20.
Hello from Glasgow, where the sun won't be up for another half an hour, and it's currently -2°C. Not much chance of it warming up much today...
Another interesting item is that although the shortest day is the 21st December, the evenings start getting brighter from the 16th December.

dg writes: Yes, we've covered that before.

Mornings don't start getting brighter until January 3rd.
Fascinating stuff. Thank you.
Fascinating explanation of why our solar panels aren't doing much at this time of year!
We tend to think only of the shortened daylight hours but the low sun is the case of the gloom. It's worth noting, I think, that there is a double hit. Not only does each square meter of surface get less warming effect from sunlight coming in at such a low angle but also that sunlight has passed through a great distance of atmosphere (a higher air-mass number) and therefore more of its energy has been absorbed by the gasses and water vapour.
Interesting stuff. But I’d like the graphs a bit more if you smoothed the lines, which is easy enough if they are produced in Excel.
A few years ago I had a play with solargraphy (long term pin hole camera left in one place) to catch the height of the sun over 6 months

I got one good image overlooking tower bridge

https://flic.kr/p/9VkfEQ

The lighter hoops in in the sky are the sun's path every day from dec21 to june 21
Very interesting. I think you're like the BBC You inform, educate and entertain!
And if you want a complete contrast to London's variability then try Singapore. Being so close to the equator there is virtually no variation in day length or sun height over the year. I imagine you get used to the lack of change.
I remember in a geography lesson many years ago that the effect of the low angle of the sun is demonstrated by shining a torch at a piece of paper at an angle compared to holding the torch directly over the paper. The torch produces the same amount of light but that light is spread over a larger area so less intense. Directly above the paper the lit area is smaller but brighter. Perhaps that's what you're saying. I'm not sure. Also I believe it is true to say the every square inch of the earth gets the same Amount of exposure to sunlight when measured over a year. That clearly acts in different ways to produce different temperatures.
@Mitch
Indeed, everywhere gets the same amount of daylight over the year. But where the sun gets higher in the sky, you get more heat from it per unit area - that's why it never gets very warm at the Poles, even though you get 24 hours of daylight in the summer - the sun is never more than 23 degrees above the horizon.
The amount of heat per unit area goes as the sine of the sun's elevation, so varies more at low elevations - at 30 degrees you get half (not a third) of the intensity you get at 90. As for absorption by the atmosphere, depending on what value you use for the thickness of the atmosphere, geometry gives values of around ten times as much absorption when the sun is on the horizon compared to when it is overhead.
My only observation is that the months with the highest solar elevation (May - July) don't quite tally with the warmest ones (June - August). And the ones with the lowest elevation (November - January) differ slightly from the coldest ones (December - February).
The lag (highest temps being a month or so after highest sun-heat-input) is mainly because of the stored heat in the earth - and particularly in the sea.

What I'd be interested to know about the heat absorption variation which is mentioned, is how much of an impact that has compared to the area variation. My guess would be "not much". Partly because part of the heat absorbed by the atmosphere ends up warming the earth anyway
I love a good weather related post -
especially with lots of tables and charts to look at!
The maximum solar elevation table seems to correspond with the view I've always held of the seasons - that winter is Nov-Jan, Spring is Feb-April, summer is May-July and Autumn is Aug-Oct.

I wonder if this is how it was traditionally viewed, because now the solstices and equinoxes fall exactly mid-way through the season - hence being called mid-summer/mid-winter.
Thank you so much, really interesting. "Axial tilt: it's the reason for the season!"
And elevations of at least 40 to 50 degrees are needed for sunlight on your skin to be strong enough for you to make vitamin D. Apparently most people do not eat enough foods sufficiently high in vitamin D for diet alone to prevent depletion of their stored levels over the winter.

So southerners get around 6 months of the year to stock up naturally, at least if they are outside around noon in the spring and autumn. Those further north have fewer weeks to make their own vitamin D.
I randomly stumbled over this article as first result on Google looking for "angle of the sun, UK".

And it was *super* and exactly what I needed. I obvs already knew the general principles but I was looking for the angles and ideally an idea of where in the east and west the sun breaks the horizon depending on the month and blow me if it wasnt *all* here in one place. Superb. Amazing. *Applause*.










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