I'm Swedish/Finnish and live in Southern California. I stopped taking Vitamin D now that it's gotten sunny enough I need sunglasses again. I go outside in the sun with my running shorts on at noon. I go hiking in the sun all day on the weekend. This should be enough I think.
I've heard that the reason white people are fair is because of the low level of sun in Northern Europe. You cannot take a baby to term without adequate Vitamin D. People who were able to soak up more Vitamin D from the weak Northern European sun had more babies and thus the fair skin became an adaptation that survived. It ought to be enough sun then to go out in the noonday sun and expose yourself for a few minutes.
Female, 5'3", 50, Max squat: 202.5lbs. Max deadlift: 225 x 3.