I'm not a Medical Doctor or even a PhD. However, I would recommend everyone get their vitamin D levels checked, regardless of what season it is. Almost everyone has levels that are far too low. Do your own research, talk to your Doctor, etc.

Also just go outside naked (or close to naked to increase absorption surface area.

Why more harm than good?

Thanks for the inspiration! I need to be getting outside more during the winter and I also made sure to do tons of shirtless walks in the summer and spring so hopefully I don't need vitamin D supplements.

Nonsense. You need much more sun and have to eat animal offal to raise your vitamin D3 levels. Most people don't eat offal and have too little contact with their skin. Chest arm face. They are mostly covered in winter.