Bay Area? San Francisco you mean? That's fine :) but a new tech corridor all the way in the north...

SF is extremely cold. You can't ever spend the whole day in a t-shirt, not even in the summer.

Extremely cold is pushing it. Chilly is probably more apt.

It generally has a mid-level UV index, so you feel warm in direct sunlight, but the humidity is very low so the 'breeze' feels cold. Some may find this unpleasant.