Nationwide Annual Average Daily UV Irradiance (J/m²), 2020

The UV index, which measures the intensity of ultraviolet (UV) radiation from the sun, varies across states in the United States, resulting in differing levels of sun exposure risk for residents. States such as Arizona and Florida consistently record high UV indexes, often reaching levels of 10, signifying very high UV exposure, especially during peak daylight hours.

***UV Index values shown are averages for the noon hour. The UV Index at any given time and place may be higher or lower depending on factors including the time of day, cloud cover, and altitude. ***Amounts shown are displayed in Joule per square meter (J/m²).
Chart: Sweet JamesSource: World Population Review Created with Datawrapper