UV Index Today provides national and local UV index forecasts for 40,000+ cities in the United States. Our forecasts include the real-time UV index, the hourly UV index, and the UV Index forecast for the next five days. Our forecasts are built using data provided by NOAA.

Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of the total electromagnetic radiation output from the …

Jul 16, 2025 · Ultraviolet (UV) radiation is a form of non-ionizing radiation that is emitted by the sun and artificial sources, such as tanning beds. While it has some benefits for people, including the creation of Vitamin D, it also can cause health risks.

Aug 24, 2023 · Ultraviolet (UV) radiation is one part of the electromagnetic spectrum of radiation that reaches Earth from the sun. It is a form of light energy situated on the spectrum just beyond visible...

Jul 19, 2025 · The ozone layer effectively blocks almost all solar radiation of wavelengths less than 290 nm from reaching Earth’s surface, including certain types of ultraviolet (UV) and other forms of radiation that could injure or kill most living things.

1 day ago · The sun's ultraviolet (UV) rays can cause permanent damage to the skin and are also the leading cause of skin cancer. Understanding the UV index and its levels in your area is essential when ...

Apr 23, 2025 · This easy guide breaks down the UV Index scale, explains UV exposure risk and shows you how sun safety tips, daily UV forecasts and factors like ozone and cloud cover affect safe UV levels.

Jul 14, 2025 · The ultraviolet (UV) index measures the intensity of harmful sun rays and can help you understand when to avoid the sun to protect your skin and eye health from serious damage. When outdoors, a high UV level can indicate three major health risks.

Jun 2, 2025 · Sun Health Effects Learn about the health effects of UV radiation, tips for staying safe in the sun, and Don't Fry Day.

3 days ago · The ultraviolet (UV) spectrum is an invisible segment of light, extending beyond the violet end of the visible spectrum. This electromagnetic radiation surrounds us, originating from both natural and human-made sources.