Ah, i liked the hawaiian snow when i grew them years ago. I had 6 seeds stashed, gave 3 to a family member recently and he grew them out. Nice smoke.
No more or less is a good thing. The burn wont necessarily go away once there.
As far as harvest... hmm, how cold? I would assume not freezing as your coastal, correct? I wouldnt worry about temps so much. How much rain do you get currently? Mold or mildew might be a bigger enemy than cold. I live in a very cold area and my plants make it for weeks at just above freezing.
She's been flowering for 13 weeks? Thats about right for harvest time.. Not sure if you have access to a microscope/magnifier that you can look at the trichomes with? That would help, if you have some amber trichs, rest milky, shes done.