UVB rays cause tanning and skin cancers in the superficial layer of the skin and are prevalent in the mid day of the summer season, from 10 a.m. to 4 p.m.

UVA rays are up to 50 times more common than UVB rays and penetrate to the deep layer of the skin (the dermis). They cause aging by damaging collagen and contribute to skin cancer. UVA rays penetrate clothing and un-tinted glass. — Imber