The UV Index is a simple numerical scale that indicates the strength of ultraviolet radiation from the sun at the surface. Values range from 0 upward; higher numbers mean greater potential for skin and eye damage.

The index takes into account the sun’s elevation, ozone amount, cloud cover, and surface reflectivity. It is typically forecast for solar noon, when UV is strongest. Categories range from low to extreme, with corresponding recommendations for sun protection.

Public weather services issue the UV Index alongside other daily forecasts. People use it to decide when to seek shade, wear protective clothing, or apply sunscreen. The index is especially useful at higher elevations and in tropical regions where UV levels can be very high even on partly cloudy days.

• Scale of ultraviolet radiation strength
• Forecast for peak daytime conditions
• Guides sun-protection decisions
• Higher values increase risk of damage