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I'd say it's more on the sunny side. However, the immediate coast suffers from frequent "May grey / June gloom" fog and low cloud in late spring/summer. A little bit inland sunshine hours increase rapidly.
Location: The western periphery of Terra Australis
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Both SF and SD are prone to summer marine layer fog, which makes them seem gloomier than they actually are. San Fran averages about 2880 hours of bright sunshine - still bright by any standards. The north coast of California is very foggy and it gets weeks of winter cloud, so the jury's out on whether THAT is cloudy or sunny. As SAB said inland from SF are very sunny. Sacramento is ridiculously sunny in summer with an average 27-30 clear days in July.
Both SF and SD are prone to summer marine layer fog, which makes them seem gloomier than they actually are. San Fran averages about 2880 hours of bright sunshine - still bright by any standards. The north coast of California is very foggy and it gets weeks of winter cloud, so the jury's out on whether THAT is cloudy or sunny. As SAB said inland from SF are very sunny. Sacramento is ridiculously sunny in summer with an average 27-30 clear days in July.
Somewhere I read that Sacramento averages 14 hours of sun per day in July, which would have to be very close to the maximum possible.
Some annual % of possible for California (some inland parts get 97% possible sun in July):
Eureka 51 Fresno 79 LA 73 Redding 88 Sacramento 78 San Diego 69 San Francisco 66. By world average standards all of these except Eureka can be regarded as sunny.
Yes 14 hours for a place at that latitude is close to 100% sunshine.
Perth averages (only) 10.8 hours in January but it is at a lower latitude. Even so, it gets 17 clear days and 5 cloudy days.
What counts as a "cloudy day" in Perth?
In Toronto, it probably means over 90% cloud cover, all hours of the day.
These kinds of conditions means there are no distinct shadows anywhere, (feels like no shadows)
and it's dim to fairly-dark everywhere indoors, even mid-afternoon.
Toronto can get that anytime of year, even in July. (though it's rarer in summer)
*Somehow, I can't see a place like Perth being able to get those sky conditions in summer...
Location: The western periphery of Terra Australis
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Quote:
Originally Posted by ColdCanadian
What counts as a "cloudy day" in Perth?
In Toronto, it probably means over 90% cloud cover, all hours of the day.
These kinds of conditions means there are no distinct shadows anywhere, (feels like no shadows)
and it's dim to fairly-dark everywhere indoors, even mid-afternoon.
Toronto can get that anytime of year, even in July. (though it's rarer in summer)
*Somehow, I can't see a place like Perth being able to get those sky conditions in summer...
I believe they (the BOM) divide the sky into 'oktas' - eighths of the visible sky. Clear would be 2 oktas or 2/8ths or less, partly cloudy between 2 and 6 I believe and cloudy 6/8ths and above. They average the readings for 9am and 3pm to derive the 'cloudiness' of a particular day. So say, if it was 1 okta at 9am but 7 oktas at 3pm you'd have an average of 4/8 = partly cloudy.
I believe they (the BOM) divide the sky into 'oktas' - eighths of the visible sky. Clear would be 2 oktas or 2/8ths or less, partly cloudy between 2 and 6 I believe and cloudy 6/8ths and above. They average the readings for 9am and 3pm to derive the 'cloudiness' of a particular day. So say, if it was 1 okta at 9am but 7 oktas at 3pm you'd have an average of 4/8 = partly cloudy.
yes, well if we're talking 1/8ths of the sky,
I would estimate "cloudy" days (which = zero blue misery) in Canada would be no lower than 7.5 oktas.
6/8's is 3/4's....
That counts as cloudy???
That would probably be called "mainly cloudy" here.
(most days with few hours of any blue patches are classed "mainly cloudy" here)
*Does that mean days with zero-blueness are so rare in Australia, it's not considered worth keeping record of, in most places?
**Hard to see the horizon in the city, but my best guess is that we have 50 days a year of zero "blue-ness" on the horizon.
(at least as many days annually that we have 2 oktas or less )
Last edited by ColdCanadian; 05-05-2009 at 07:56 PM..
It's simpler to simply talk in terms of sunshine hours. They aren't perfectly correlated with the amount of cloud anyway. If the sun is shining, I don't care how much the rest of the sky is coverted.
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