Ah I got you now.. I understand. 

Camborne's max of just over 5 was about the same as Gibraltar's today. Good on ya Cornwall. We'll get a 10 out of you yet!

Poor index for Gibraltar but a fairly average one for Cornwall.

I imagine there were some especially high values for April today given the extremely clear skies and low humidity (it was 31% or less for 5 hours here, bottoming out at 27%!).

Forecasts were in the 5s generally, maybe a local 6.

Missed your post SC- but I think you would be right. Sunday was brilliant blue. Camborne managed a 5.6 and Chilton a 5.4 but still nothing from Reading or Swansea- I'm giving up hope there. For the far South, Roger (Forest Edge) has a consistent recorder. Think I'll drop him a PM.

Today, in between the clouds, the sun feels very strong indeed,out of the wind. 

Chilton 6.0 yesterday; Camborne 6.3 today.

6.3 in Camborne Roger; I note Art's comment in the CET threads, which I interpret as that Hadley cast off a bit of responsibility for publishing CET data on time. Perhaps Reading & co feel no responsibility, although I'm not sure of the funding there.

Camborne hit 6 today but nearly 7 yesterday. Love the serrated graph- all that cumulus cloud drifting by. Could be a clear 7+ tomorrow.

Camborne 6.9, Chilton 6.8

Chilton 6.9

Camborne 7.4

Bertie, I have not exceeded 5.8 yet and I think you are misreading the DEFRA graph bands , it should be Camborne 6.4 and Chilton 5.9 !

Edit: it reached a 6.3 index today

https://uk-air.defra.gov.uk/data/uv-index-graphs?site=Camborne

I'd say Camborne reached about 7.6 today based on the above.

Zero means no UV at all, of course, and it's where the graph starts the day. As soon as there's any UV, that counts as 1 on the scale. Based on that, Bert's readings are fine.

(The Met Office is predicting 7 here tomorrow, which also fits with the figures seen at the likes of Camborne - it's definitely in the 7s down there!)

Sorry if I am confusing the reading of these graphs here!

If you assume the uv scale starts at zero , then the first green band covers zero to 1.0, second green band 1.0 to 2.0 and so on.

i.e all the uv numbers are rounded up, does this not make sense?

Why do you assume this scale starts at zero Roger, rather than the bottom of 1? Zero means no measurable UV- above that, if it's measurable, as Darren says, it enters the first measurable band: band 1. Otherwise one has to assume that the line at the top of the labelled band is the first threshold that that labelled band (beneath it) is reached. That would be odd sense- the model would be visually ineffective, and it is a visual model. Note also on the vertical scale there is no zero labelled at all. 

It reminds me of the mistake sometimes portrayed on time lines of History: there is a line half way along between 1BC and AD1- as if someone has invented a year zero; but of course, there is no year zero- it was 1BC up to (not getting into the historical debate about the birth) the moment Jesus was born, then it immediately became AD1- not AD 0.5 for the first half year after the birth. When did this Millenium start? Everybody got excited on 31st December 1999, but they were a year early. The Millenium (not its misleading digits) started on 1st January 2001- one thousand years after 1 January AD1.

Similarly, if it's measurable UV, it's UV1. And, if you read back through the thread, sometimes your station reads higher than the listed ones, and often it ties in very nicely. That would preclude the argument, or else mean Camborne can be expected to be lower?

I suspect the disparities this time are, genuinely, regional variations in UV- an interesting synoptic set up with very cool nights for mid May might lead to differences in O3 for example, or other pollutants. Alternatively, since hitherto the readings in the NF have been comparable with Reading, maybe there's a technical difficulty.

Also, Camborne could be expected to be a level higher if the old MetO info (7 rare, 8 only in Camborne) is to have ever been relevant- surely due to air quality as well as the slight latitudinal advantage it has over the rest of S England.

Hope we all get some sunny 7s soon!

Edit: Chilton got its first 7.0 today, and Camborne a heady 7.7.

Felt right outside.

I think you are right as UV indexes can be inbetween for example 1.3C or 4.6, and that if it reaches the top of the defra number then it is indeed that number. 

Also those talking about the met office forecast I've  come to suspect these are rounded to the nearest whole, and also only represent the top likely index for that day based on whichever run they are derived from. The past 2 days down here in Portsmouth have also had 7's in the forecast but in reality the highest recorded at at a local private station was 6.3. 

Also defra have more detailed graphs available but apparently only for certain stations and upon request that give indications of how accurate the automated graph are as human input is put to use 

That's a very good point tdf, and one I'd overlooked. Of course, health is the key reason UV data is included in forecasts. Your point reaffirms what I have explained.

Chilton 6.7 yesterday, but only 2.9 today.

Last 2 days: Camborne- 6.8, 7.1; Chilton- 6.8, 7.0.

So a 7 in inland S Britain.

Reading is back on and backdated to the cut-off date. Highlights:

10/4/19: 4.2

18/4/19: 4.8

21/4/19: 5.0

30/4/19: 5.9

12/5/19:6.5 (5 days 12th to 16th inc. >factor 6).

21/5/19: 6.7

7.6 in Camborne, 7.3 in Chilton and- guess what. Having cheered Reading's return from the flatline, it's turned off today. Churlish.

Chilton top of the pile with 7.6. Ahead of Camborne.