I own both, never worn the Sitka core heavyweight in the field though.
I just went on a backpacking trip in the Yosemite high country. The temps were 50 during the day with howling winds, and low 20’s at night. The Klamath is surprisingly wind resistant. More wind resistant than my peloton 240.
I think because of the wind resistance alone I’m going to go with the Klamath over the Sitka heavyweight on my next trip.
There are some advantages to the Sitka piece though. They both have hoods that zip up over your mouth/nose. The Sitka piece is looser in that area, which is less warm but more comfortable. The Sitka piece is also longer in the tail so it can keep your butt warmer. It’s also softer on the inside because it’s a brushed fleece vs the Klamath which is a grid fleece interior.
Hope this helps.
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