Visiting California in Feb

Hi, 25F from Taiwan, and I will be visiting SF in February. This will be my first visit to the US, kinda nervous especially about the weather, my friend says it’s different than the cold weather in Japan. (I’ve visited Japan during Jan before, went high in the mountains) How should I dress? What jacket should I bring? or is there any influencers based in the north Cali area that I could follow? Thanks! appreciate every comment:)