Reading the UV Index: The Exact Number That Means 'Put Sunscreen On'
That little UV number in your weather app has a clear threshold - here's the reading where protection stops being optional.
The EPA UV Index runs from 0 to 11+, advises broad-spectrum SPF 30 or higher from a reading of 3 (moderate) upward, and notes that nearly half the day's UV arrives between 10 a.m. and 4 p.m.
The EPA frames the index as an action tool, advising broad-spectrum SPF 30 or higher, shade, and protective clothing once the reading reaches moderate, around a 3.
Questions we get a lot
At what UV index should I start wearing sunscreen?
The EPA advises broad-spectrum SPF 30 or higher once the UV Index reaches 3 (moderate) and above. Below that, protection matters less for most people, though sensitive skin may still benefit. The index is designed precisely to make this call simple.
What time of day is UV strongest?
The EPA notes that nearly half of the day's UV radiation arrives between 10 a.m. and 4 p.m. That midday window is when shade, clothing, and reapplied sunscreen matter most, regardless of how warm it feels.
What does the 0 to 11+ UV Index scale mean?
The EPA UV Index runs from 0 upward, with no fixed ceiling, so very high readings are written as 11+. Higher numbers indicate a greater risk of skin and eye damage from unprotected exposure and a shorter time to harm. The scale is meant to guide everyday protection choices.
r/SkincareAddiction: 'What UV index is actually low enough to skip sunscreen? My app says 2 this morning.'