# Understanding UV Levels and Protecting Your Skin
The sun emits ultraviolet radiation in three types: UVA, UVB, and UVC. While UVC gets absorbed by the atmosphere before reaching Earth, UVA and UVB penetrate our skin and carry real health consequences. Some UV exposure matters for vitamin D production and bone health, but excessive exposure accelerates skin aging and increases melanoma risk.
UV levels vary by location, season, and time of day. The UV Index, measured on a scale from 0 to 11 and higher, tells you how intense the sun's rays are on any given day. At Index 3 or higher, sun protection becomes necessary. Midday hours between 10 a.m. and 4 p.m. carry the strongest UV rays, particularly during summer months.
Effective protection starts with broad-spectrum sunscreen containing SPF 30 or higher, which blocks roughly 97 percent of UVB rays. Apply a quarter-teaspoon to your face and one teaspoon to your neck and chest. Reapply every two hours, or immediately after swimming or sweating. SPF 50 offers slightly better protection (98 percent) but requires the same reapplication schedule.
Beyond sunscreen, layered protection works best. Wear lightweight, long-sleeved clothing with UPF ratings, seek shade during peak sun hours, and use wide-brimmed hats. UV-blocking sunglasses protect delicate eye tissue from cataracts and macular degeneration later in life.
Children need special attention. Their skin contains less melanin and absorbs UV damage more readily than adult skin. Keep infants under six months in shade entirely, and apply sunscreen to older children at least 15 minutes before outdoor time.
Regular skin checks matter too.