I live in Oregon as well (up near Portland). Our barn will start blanketing in the evenings when it starts getting down to about 45F and then during the day when it is staying cold and wet. Most of the horses grow fairly good coats around here. My boy doesn't get blanketed except under a few of the extreme conditions we've had but as a draft he's never needed it (and I can't find a good size 103 blanket for him).
I know people that show will start blanketing sooner.
My horse doesn't get wooley like a lot of horses...she gets a tiny bit of fuzz. I have a blanket for her because she is in a pasture and there are limited indoor stalls so she will have the oppurtunity to be in the pasture all year long with access to an outdoor stall if it begins to rain.
Hmmmm was just wondering this myself. Hunter is already starting to get a wee wooly and its not even cold yet. Sheesh he is like a llama in the winter time. Might start putting the light blanket on him soon.
I live near Solon (near Portland, Oregonians unite! ) and I'm going to start blanketing Lacey in about 2-3 weeks. I'm going to start out with just a light blanket and move up from there. I really don't want Lacey to grow much of a winter coat (ie, only about 2 inches of fur instead of her usual 4 inches is my goal) because I do work her in the winter and I don't want to end up with a sweaty, woolly horse on my hands.
I didn't blanket last year here in San Antonio, but I did blanket sometimes in SC the year before when it was below freezing at night and didn't get above 35-40 during the day. I should say I only blanketed at night then...not during the day. That was the first year Cope had ever been blanketed in his life. He was 13-14 then. We never put blankets on them at home in Alabama. My in-laws also don't blanket their horses...ever...and they're in Illinois.