UV index 4 from 29 March

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Exotic Life
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Re: UV index 2 possible this weekend

Post by Exotic Life » Mon Feb 24, 2014 7:05 pm

Shirt off with 15C in February? Too cold for me, it needs defitenely be warmer then that before I take of my shirt.

However, I had lunch also outside today and need to agree that it don't even know how many lunches I had outside this winter.


otorongo
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Re: UV index 2 possible this weekend

Post by otorongo » Mon Feb 24, 2014 7:12 pm

Next time, Cordy.

Unfortunately there are no spots around Victoria where it would be okay to sunbathe naked icon_thumbdown Central London is very stiff.

Looks like index 2 is the norm these days, the next milestone will be index 3, not sure when that will come but I think in around 2 weeks?

This week I'm planning to work from home on Wednesday as it's looking the strongest day. Lots of pictures of the garden and neighbourhood will be taken :D


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cordyman
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Re: UV index 2 possible this weekend

Post by cordyman » Mon Feb 24, 2014 7:23 pm

otorongo wrote:Next time, Cordy.

Unfortunately there are no spots around Victoria where it would be okay to sunbathe naked icon_thumbdown Central London is very stiff.

Looks like index 2 is the norm these days, the next milestone will be index 3, not sure when that will come but I think in around 2 weeks?

This week I'm planning to work from home on Wednesday as it's looking the strongest day. Lots of pictures of the garden and neighbourhood will be taken :D

Look forward to the pics icon_salut

The sun is noticeably higher dare I say it each day?

I sit with an office window which has the morning sun dazzling me around 10am, usually closing the blinds at this point and reopening after lunch once its moved round. This week the sun is nearly above the top of the window and in line with the gutter so will no longer dazzle me, it needs to go up by another foot or so from my seated perspective! Can't beat looking out onto blue skies icon_sunny


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Re: UV index 2 possible this weekend

Post by GREVILLE » Mon Feb 24, 2014 10:59 pm

otorongo wrote:Next time, Cordy.

Unfortunately there are no spots around Victoria where it would be okay to sunbathe naked icon_thumbdown
I was there at 3pm today and can vouch that I saw no naked sun revellers as I assume the clouds had removed all hope of index 2 and Otorongo got fed up and went home. :shock:


otorongo
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Re: UV index 2 possible this weekend

Post by otorongo » Tue Feb 25, 2014 9:21 am

Exotic Life wrote:Shirt off with 15C in February? Too cold for me, it needs defitenely be warmer then that before I take of my shirt.
Really? I know you're at a slightly higher latitude, but it's only 1 deg or so.
Maybe you just don't know how to do it...

I've learned to leverage the power of the sun and now do it automatically (unless it's really hot, that is). It was definitely too hot in the t-shirt.

Most people are very inefficient - they sit at the wrong angles, wear the wrong colours, and cover their skin lightly when putting more layers on the already covered parts would make them warmer without increasing the area deprived of light.


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Exotic Life
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Re: UV index 2 possible this weekend

Post by Exotic Life » Tue Feb 25, 2014 2:10 pm

otorongo wrote:
Exotic Life wrote:Shirt off with 15C in February? Too cold for me, it needs defitenely be warmer then that before I take of my shirt.
Really? I know you're at a slightly higher latitude, but it's only 1 deg or so.
Maybe you just don't know how to do it...

I've learned to leverage the power of the sun and now do it automatically (unless it's really hot, that is). It was definitely too hot in the t-shirt.

Most people are very inefficient - they sit at the wrong angles, wear the wrong colours, and cover their skin lightly when putting more layers on the already covered parts would make them warmer without increasing the area deprived of light.
If I draw a line I will be somewhere in North London, so not that big difference. It is just, 15C is not warm enough. I am not the only one, No-one (Okay, lot of people because I don't know 17 million people) is wearing shorts or t-shirt on days like we had recently. People, won't even think here about taking your shirt off. People went out for some drinks in the early spring sunshine but with jackets on.

I would almost say that UK people feeling temperatures like this warmer then we do because we have more summerheat. However this is not going to work as you are from Londen and that is quite similair, or even warmer then some parts of Holland.

That made me to have one conclusion, maybe it is just you then. :lol:


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Re: UV index 2 possible this weekend

Post by otorongo » Tue Feb 25, 2014 2:51 pm

Exotic Life wrote:If I draw a line I will be somewhere in North London, so not that big difference. It is just, 15C is not warm enough. I am not the only one, No-one (Okay, lot of people because I don't know 17 million people) is wearing shorts or t-shirt on days like we had recently. People, won't even think here about taking your shirt off. People went out for some drinks in the early spring sunshine but with jackets on.

I would almost say that UK people feeling temperatures like this warmer then we do because we have more summerheat. However this is not going to work as you are from Londen and that is quite similair, or even warmer then some parts of Holland.
I've seen people go around shirtless on overcast and cold (barely above freezing) February days in London.
Many cyclists wear shorts all year round here, regardless of the weather, and short sleeves are very common in the winter.
If you go to places like Malaga in the winter, you can easily tell who is who... those in shorts and t-shirts (off on the beach) are Brits, those in light jackets are Germans, those in thick jackets with scarves, gloves and hats are Spaniards :lol:

15C with 29 deg. sun in a sheltered spot is beach weather, you can get quite a lot out of your day. Had I been in the garden I would have worn shorts only, and optionally flip-flops for the muddy patches, but those are not essential as we don't have scorpions ;)

As long as the sun is above a certain strength, it doesn't matter that much if it's 0C or 15C, since the heat you feel comes from the sun rather than the surrounding air. The actual air temperature only makes a difference when a cloud moves in.


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Re: UV index 2 possible this weekend

Post by otorongo » Sun Mar 02, 2014 1:10 pm

We'll soon be entering index 3 territory... around 14 March, maybe earlier if the skies are clear.


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stephenprudence
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Re: UV index 3 from ~14 March

Post by stephenprudence » Sun Mar 02, 2014 5:33 pm

As much as I hate to burst anyone's balloon, the weatheronline UV index is calculated a little different to the Met-office and other Meterological organisation's index, in that a UV of 3 on weatheronline is equal to 1 on the standard indicator. So it's not quite as good as it seems.

Also the heat of the sun (infrared output), has absolutely nothing to do with the strength of the UV, which cannot be felt (until you burn)
Last edited by stephenprudence on Sun Mar 02, 2014 5:34 pm, edited 1 time in total.
Heswall, Wirral, UK
USDA equivalent average temperature zone: 9a/RHS zone 3
AHS Heat Zone: 1
Last 5 winter minimums:
2007: -0.1C, 2008: -4.2C, 2009: -5.7C, 2010: -10.5 (record), 2011: -4.9C, 2012: -5.3, 2013: -4.5C (so far)


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cordyman
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Re: UV index 3 from ~14 March

Post by cordyman » Sun Mar 02, 2014 5:34 pm

stephenprudence wrote:As much as I hate to burst anyone's balloon, the weatheronline UV index is calculated a little different to the Met-office and other Meterological organisation's index, in that a UV of 3 on weatheronline is equal to 1 on the standard indicator. So it's not quite as good as it seems.
how does that work then? :lol:


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stephenprudence
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Re: UV index 3 from ~14 March

Post by stephenprudence » Sun Mar 02, 2014 5:36 pm

cordyman wrote:
stephenprudence wrote:As much as I hate to burst anyone's balloon, the weatheronline UV index is calculated a little different to the Met-office and other Meterological organisation's index, in that a UV of 3 on weatheronline is equal to 1 on the standard indicator. So it's not quite as good as it seems.
how does that work then? :lol:
I don't know.. ask weatheronline.

http://www.metoffice.gov.uk/weather/uk/ ... st_uv.html

This one is much more accurate.

This one is quite good too..

http://www.uvawareness.com/uv-index/uv- ... on=Heswall
Heswall, Wirral, UK
USDA equivalent average temperature zone: 9a/RHS zone 3
AHS Heat Zone: 1
Last 5 winter minimums:
2007: -0.1C, 2008: -4.2C, 2009: -5.7C, 2010: -10.5 (record), 2011: -4.9C, 2012: -5.3, 2013: -4.5C (so far)


otorongo
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Re: UV index 3 from ~14 March

Post by otorongo » Sun Mar 02, 2014 5:52 pm

I don't think it's a difference in the way the index is defined / calculated, but a difference in the forecast. If the MetOffice forecasts an overcast day their UV index forecast must follow suit.

What this thread is about is the maximum UV index *possible*, i.e. the index we'll get if the sky is clear. It's an indication of how high the sun climbs above the horizon; it's independent of the weather and depends solely on the latitude and date (ok, altitude and proximity to large bodies of water can make a difference, as can sn*w cover, but those are negligible in London).

If Weatheronline shows a forecast of index 3 on the 14th it *must* mean that index 3 is possible on that day, and it *may* be possible at an earlier date, but is not expected to be reached due to the cloud cover.

But if what you say is true, Stephen, then I'd say it's not a very useful definition of UV index if roughly half of the year - from the Autumnal Equinox to the Spring Equinox - all falls into the bucket of "UV index 1"... not very useful for the UK anyway. In that case I choose Weatheronline's definition :)
Last edited by otorongo on Sun Mar 02, 2014 5:58 pm, edited 1 time in total.


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stephenprudence
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Re: UV index 3 from ~14 March

Post by stephenprudence » Sun Mar 02, 2014 5:58 pm

UV 3 is not possible in the UK before the end of March in most cases. I used to follow the UV quite closely for a long time.. UV 3 has never been reached before March 15th at least, it's an impossibility, the UV and solar output is a very rigid thing, in that in can't deviate like temperatures can. The infrared output of the sun can vary throughout the year though, Ive felt the sun feel quite warm in December despite being as low in the sky as it gets.

But then we are only a few hundred miles from Arctic circle, so our sun index is going to be very inferior for longer periods, so it's not surprising at all.
Last edited by stephenprudence on Sun Mar 02, 2014 6:00 pm, edited 1 time in total.
Heswall, Wirral, UK
USDA equivalent average temperature zone: 9a/RHS zone 3
AHS Heat Zone: 1
Last 5 winter minimums:
2007: -0.1C, 2008: -4.2C, 2009: -5.7C, 2010: -10.5 (record), 2011: -4.9C, 2012: -5.3, 2013: -4.5C (so far)


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cordyman
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Re: UV index 3 from ~14 March

Post by cordyman » Sun Mar 02, 2014 6:00 pm

I can't see how it can be uv index 1, the sun recently has had proper heat in it, something not possible in January


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stephenprudence
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Re: UV index 3 from ~14 March

Post by stephenprudence » Sun Mar 02, 2014 6:00 pm

cordyman wrote:I can't see how it can be uv index 1, the sun recently has had proper heat in it, something not possible in January
As I explained, the heat is the infrared output, not the UV.. the UV has nothing to do with how warm the sun feels.
Heswall, Wirral, UK
USDA equivalent average temperature zone: 9a/RHS zone 3
AHS Heat Zone: 1
Last 5 winter minimums:
2007: -0.1C, 2008: -4.2C, 2009: -5.7C, 2010: -10.5 (record), 2011: -4.9C, 2012: -5.3, 2013: -4.5C (so far)


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