"Except during the summer months, the skin makes little if any vitamin D from the sun at latitudes above 37 degrees north (in the United States, the shaded region in the map) or below 37 degrees south of the equator. People who live in these areas are at relatively greater risk for vitamin D deficiency." https://www.health.harvard.edu/staying-healthy/time-for-more...

That roughly corresponds to San Fransisco on the west coast and Richmond, VA on the east coast. So, the impact will probably be minimal for many people.