Oregon live listened to the Twilight DVD commentary and they were pretty amused that the cast and crew seemed to be a bit baffled and unprepared for the local weather.
DVD Commentary: “The weather kept changing.”
Oregon Live Response: “OK, tell us something we don’t know.”
They give their whole rundown here.
It looks like they haven’t quite adapted yet as reports from the set this weekend had Taylor Lautner and Kristen Stewart wearning Nike’s and lighter weight jacket on the freezing cold and damp beach. The locals who stopped by the filming were all in boots, knit hats, and down jackets.