The UV Index Will Peak Soon — Here's What That Means
Late spring is when UV starts climbing toward its summer high.
UV is strongest near the summer solstice and around solar noon, when the sun is highest and its rays travel through the least atmosphere; the UV Index reaches its yearly peak in late June for most of the Northern Hemisphere.
Dermatologists advise sun protection whenever the UV Index is 3 or higher — a threshold most regions cross daily through the late-spring-to-summer climb.
Questions we get a lot
How does sunscreen actually work?
Sunscreens use UV filters in two groups. Organic ('chemical') filters such as avobenzone absorb UV and release it as a small amount of heat. Mineral ('physical') filters — zinc oxide and titanium dioxide — mainly absorb UV and also scatter some. Both cut how much UV reaches living skin cells.
What does the UV index mean and when should I protect my skin?
The UV Index, from the EPA and WHO, rates the strength of midday UV on a scale from 1–2 (low) to 11+ (extreme). Dermatologists generally advise sun protection whenever it reaches 3 or higher. It appears in most weather apps and rises with sun elevation, altitude and proximity to the equator.
Why does UV get stronger in late spring and summer?
As the seasons turn toward summer the sun climbs higher in the sky each day, so its rays strike more directly and pass through less atmosphere. That raises ground-level UV, which peaks around the June solstice and at solar noon — so the same midday hour delivers far more UV in June than in March.
r/SkincareScience: 'Can someone explain UVA vs UVB like I'm five?'