September in the Pacific Northwest means the clouds roll in and don't leave until July. That's not entirely true with global warming/climate change, but we still have more than our fair share of gloomy days. Seattleites don't tan, they rust.
It's hard *not* to be seasonally affected living here. The one thing I really appreciated when I was back East caring for my mom, was the brilliant sunshine in December. No lack of Vitamin D there!