The UV Index is a measure of the strength of ultraviolet (UV) radiation from the sun. It predicts the risk of UV overexposure on a scale of 0 (minimal risk) to 11+ (very high risk) . The higher the UV Index, the greater the strength of the sun’s UV rays and the faster you may burn. The UV Index is calculated on a next-day basis for dozens of cities across the United States, taking into account clouds and other local conditions that affect the amount of UV radiation reaching the ground in different parts of the country.

The UV Index scale used in the United States conforms with international guidelines for UVI reporting established by the World Health Organization. The scale is color-coded and ranges from 0 to 11+, with each level indicating a different level of risk and recommended sun protection measures:

• 0 to 2: Low (green) - no protection needed
• 3 to 5: Moderate (yellow) - protection needed, seek shade during late morning through mid-afternoon, wear protective clothing, a wide-brimmed hat, and sunglasses, and generously apply broad-spectrum SPF-15 or higher sunscreen on exposed skin
• 6 to 7: High (orange) - extra protection needed, be careful outside, especially during late morning through mid-afternoon, if your shadow is shorter than you, seek shade and wear protective clothing, a wide-brimmed hat, and sunglasses, and generously apply a minimum of SPF-15, broad-spectrum sunscreen on exposed skin
• 8 to 10: Very High (red) - take all precautions, avoid being outside during midday hours, seek shade and wear protective clothing, a wide-brimmed hat, and sunglasses, and generously apply a minimum of SPF-15, broad-spectrum sunscreen on exposed skin
• 11 or more: Extreme (purple) - take all precautions, avoid being outside during midday hours, seek shade and wear protective clothing, a wide-brimmed hat, and sunglasses, and generously apply a minimum of SPF-15, broad-spectrum sunscreen on exposed skin

It is important to note that some exposure to sunlight can be enjoyable, but too much could be dangerous. Overexposure to the suns UV radiation can cause immediate effects such as sunburn and long-term problems such as skin cancer and cataracts. Therefore, it is important to check the UV Index daily and take appropriate precautions to prevent overexposure to the suns rays.