Do the mountains of British Columbia protect the West Coast from arctic fronts? (climate, warm)

[iPwn]

i was thinking they would shield off most Arctic weather patterns, explaining why extreme cold is uncommon on the west coast.

[deneb78]

I think the mountains do help protect somewhat when the occasional arctic fronts blow through, although the arctic outflow winds in the valleys at times can be quite severe. I know the Fraser Valley has recorded windchills below -20C (-5F) before.
I think mostly though extreme cold is uncommon on the West Coast because most of the time the prevailing winds come from the Pacific Ocean which is mild compared to cold continental air in winter.

[ilovemycomputer90]

When was the last major arctic outbreak to affect California or Arizona? IIRC, Phoenix has recorded a record low in the teens.

[Infamous92]

I wish the Appalchians were taller (only when cold fronts approach).

[Zone13]

Originally Posted by ilovemycomputer90

when was the last major arctic outbreak to affect california or arizona? Iirc, phoenix has recorded a record low in the teens.

2007

[KC6ZLV]

Mountains have an effect. However, an onshore flow moderates the climates along the west coasts of continents. The British Isles is a good example. Ireland doesn't get excessively cold because the ocean moderates the temperature, and there isn't a mountain range nearby to block cold arctic air.

[wavehunter007]

…as others pointed out…the marine flow off the ocean keeps West Coast climates from ever getting very cold, and the few bouts of cold that do occur - are fleeting. This has less to do with the Mts of British Columbia. Places in middle latitudes like Seattle, London, New Zealand…etc are often 15 F or more warmer than average for their latitude in the winter months.

However, the marine flow is a two edged sword:

Middle and high latitude marine West Coast climates are 15 to 20 F colder than average for their latitude in the summer months. Places like Seattle, London, or New Zealand are 15 to 20 F colder than comparable locations in the interior/eastern areas of most continents. Also, because of the constant higher latitude flow off the oceans…West Coast marine climates are the cloudiest land climates on earth. The flow also causes upwelling making for cold ocean waters all year.

Pick your poison I guess.

[iPwn]

Originally Posted by wavehunter007

…as others pointed out…the marine flow off the ocean keeps West Coast climates from ever getting very cold, and the few bouts of cold that do occur - are fleeting. This has less to do with the Mts of British Columbia. Places in middle latitudes like Seattle, London, New Zealand…etc are often 15 F or more warmer than average for their latitude in the winter months.

However, the marine flow is a two edged sword:

Middle and high latitude marine West Coast climates are 15 to 20 F colder than average for their latitude in the summer months. Places like Seattle, London, or New Zealand are 15 to 20 F colder than comparable locations in the interior/eastern areas of most continents. Also, because of the constant higher latitude flow off the oceans…West Coast marine climates are the cloudiest land climates on earth. The flow also causes upwelling making for cold ocean waters all year.

Pick your poison I guess.

So does that mean in terms of absolute averages, Seattle is every bit as cold as Minneapolis, or colder, year round?

[nei]

Originally Posted by iPwn

So does that mean in terms of absolute averages, Seattle is every bit as cold as Minneapolis, or colder, year round?

No! Seattle is about as cold as Boston. But Minneapolis might be cold for its latitude.

[wavehunter007]

Originally Posted by iPwn

So does that mean in terms of absolute averages, Seattle is every bit as cold as Minneapolis, or colder, year round?

Attempting to compare locations based on temperature can often be difficult because one is often confused as to what temp profiles should be used: Should one compare annual mean temperature…seasonal temperature extremes (winter lows/summer highs)…growing degree days…etc? Coastal Norway has about the same about of frost as parts of interior central China 1000 miles to the south. Yet agriculturally, China is a far better climate because of the sunny days and warmer summers produces a much better growing environment. It can be confusing.

My guess is that the annual mean (yearly) temperature is the best measure of any climate. I don’t know what the annual averages are for Seattle and Minnapolis (I would guess that Seattle is 3 to 5 F warmer).