Climate Battle: Windsor, Ontario vs. Portland, Oregon

[BMI]

Originally Posted by Botev1912

Sunnier than Vancouver. I don't know who decided the 200 hour difference between the US and the other system. Portland doesn't have many hazy days, so the difference shouldn't be that big.

Back in 2013-14 era of the C-D weather forum there was much talk about this.
Someone noticed that at “border” city locations, there is consistantly a discrepency
in total amount of sunshine hours. Places like Sault Ste. Marie, Michigan as compared with
Sault Ste. Marie, Ontario. Turns out that USA (NOAA) uses different recording equipment
and set a different (lower) threshold of what is the lowest reading considered
to be “sunshine”. I can’t remember a lot of the details (was almost five years ago),
but most of the world (including Canada) uses Campbell Stokes sunshine recorders
and USA does not. That is why you have to very careful when comparing
USA sunshine stats with sunshine stats in other countries.
USA figures inflated by about 150 to 200 hrs on average.

nei and some the other veterans of the forum can chime in with more detail.

[Botev1912]

I think that difference would be lower on the west coast due to lower humidity during the warmer months.

[ilovemycomputer90]

Originally Posted by BMI

Back in 2013-14 era of the C-D weather forum there was much talk about this.
Someone noticed that at “border” city locations, there is consistantly a discrepency
in total amount of sunshine hours. Places like Sault Ste. Marie, Michigan as compared with
Sault Ste. Marie, Ontario. Turns out that USA (NOAA) uses different recording equipment
and set a different (lower) threshold of what is the lowest reading considered
to be “sunshine”. I can’t remember a lot of the details (was almost five years ago),
but most of the world (including Canada) uses Campbell Stokes sunshine recorders
and USA does not. That is why you have to very careful when comparing
USA sunshine stats with sunshine stats in other countries.
USA figures inflated by about 150 to 200 hrs on average.

nei and some the other veterans of the forum can chime in with more detail.

Yep, US sun hours are inflated. Should knock off a couple hundred hours to compare US to non-US cities.

[grega94]

Originally Posted by Botev1912

I think that difference would be lower on the west coast due to lower humidity during the warmer months.

Yeah I agree that in the west the difference wouldn't be as stark, but if you look at the trio of Vancouver, Seattle and Victoria you will see that Seattle is a bit off.

Vancouver: 1,937.5
Seattle: 2,169.7
Victoria: 2,193.3

Seattle is 232.2 hrs sunnier than Vancouver and 23.6 hrs darker than Victoria.

Seattle should be somewhere right in between Vancouver and Victoria in terms of sunshine and that would be right around 2065.4 hrs. So Seattle is about 104.3 hrs sunnier than it should be. However if you make a relationship between sunshine hours and precipitation days then the data looks like this.

Vancouver: 168.9/1,937.5 = 0.0871741935
Victoria: 135.6/2,193.3 = 0.0618246478
avg ratio = 0.0744994207
Seattle: 152.0/0.0744994207 = 2040.28432

This then means that Seattle is about 129.415679 hrs sunnier than it should be.

[Botev1912]

Still not close to 200 hours. The difference in places in California and Arizona would be even lower because they see blue skies so often.