What temperature range is necessary for a climate to have 4 seasons? (sunshine, prediction)

[B87]

That US sun index map seems wrong, 6 and 7 would be the norm in southern England in July.

[chicagogeorge]

Originally Posted by B87

That US sun index map seems wrong, 6 and 7 would be the norm in southern England in July.

It's from the EPA so I don't think it's wrong. Plus that's the Mean UV index, not the maximum.

Monthly Average UV Index | SunWise | US EPA


As for the UK 7 would definitely not be the norm....

he UV index does not exceed 8 in the UK (8 is rare; 7 may occur on exceptional days, mostly in the two weeks towards the end of June). Indices of 9 and 10 are common in the Mediterranean area.

UV forecast - Met Office


As for maximum UV, Paris and Berlin top out at 7 in June and July. NYC tops out at 9 in July
http://www.who.int/uv/intersunprogra...en/index3.html

[P London]

I do recall a uv index of 7 to be common in the summer..

[B87]

6/7 is normal in the south in June and July. I think the UK record is 9.3.

Look at the forecast, bearing in mind that the sun index in mid-August will be lower than in June or July.
http://www.weatheronline.co.uk/weath...R=0&NOREGION=1

[chicagogeorge]

^^

If the UK Met office says that 7 would be occurring only on "exceptional" days within a two week period how could that be normal?

[dunno what to put here]

Not sure how common 7 is, but 6 is common.

[Ariete]

Originally Posted by B87

That US sun index map seems wrong, 6 and 7 would be the norm in southern England in July.

It's an average map. Sunless days can have a UV index of 2, which lowers the monthly average. And the UV cap for a location is quite low for northern and central mid latitudes.

Here a UV of 7 is only possible on open sea South of Helsinki on early afternoon in midsummer, otherwise the cap is 6 for southern and 5 for northern Finland.

[chicagogeorge]

^^

That's exactly right. That map from the EPA is a Mean UV Index for July.... And I'm happy that Chicago's mean UV index in July is higher than NYC


Check out the Mean and Max for Hong Kong this month so far



Uploaded with ImageShack.us

[B87]

London would have a slightly higher UV index than Berlin, and slightly lower than Paris.

Brisbane's UV index ranges from 4 in June to 13-14 in January.

[chicagogeorge]

Here is a list of cities with average maximum UV index by month




Uploaded with ImageShack.us