My doctor told me (as he was telling me I needed to take vitamin D) that really at most latitudes in the US (including SF), the sun light is too weak and you wo

My doctor told me (as he was telling me I needed to take vitamin D) that really at most latitudes in the US (including SF), the sun light is too weak and you won’t get enough vitamin D from sun exposure. This was all to tell me that I should still take an oral vitamin regardless of how much time I was able to spend outside. Anecdote, so take it for what you will.