When we think of sunshine, most of us picture warm days, glowing skin, and that perfect summer tan. But while the sun gives us light and warmth, it also sends invisible rays that can harm our skin if we’re not careful. That’s where the UV index comes in, it’s a key measure of how strong the sun’s ultraviolet (UV) rays are and how quickly they can cause damage. The UV index helps us understand the risk of sunburn at any given time. It’s measured on a scale that ranges from low to extreme.