Pars Skin / Guide
UV index explained: what each number means
The EPA UV index scale from low to extreme, and what to do at each level.
The UV index is a daily forecast of how strong the sun's ultraviolet radiation will be, usually at its midday peak. The higher the number, the faster unprotected skin and eyes can be damaged.
The scale (U.S. EPA)
| UV index | Level | What to do |
|---|---|---|
| 0 to 2 | Low | Sunglasses on bright days. If you burn easily, cover up and use broad-spectrum SPF 30+. Watch out for reflection from sand, water and snow. |
| 3 to 5 | Moderate | Seek shade near midday. Protective clothing, a wide-brimmed hat, UV-blocking sunglasses, and SPF 30+ reapplied every 2 hours, even on cloudy days. |
| 6 to 7 | High | Protection needed. Reduce time in the sun between 10 a.m. and 4 p.m. |
| 8 to 10 | Very high | Unprotected skin can burn quickly. Minimize sun between 10 a.m. and 4 p.m. |
| 11+ | Extreme | Unprotected skin can burn in minutes. Try to avoid the sun between 10 a.m. and 4 p.m. |
The shadow rule
If your shadow is shorter than you are, the sun is high and UV is strong: time to find shade. This is a quick check when you do not have a forecast in front of you.
Things that raise your exposure
- Midday hours, roughly 10 a.m. to 4 p.m.
- Summer months and locations closer to the equator.
- Higher altitude.
- Reflective surfaces: water, sand, snow, concrete.
- Thin clouds, which let most UV through.
Use the hourly forecast
The daily number is the peak. An hourly UV forecast for your city shows when it climbs above 3 and when it drops again, so you can plan a walk, a game or yard work for the lower hours. Then remember to reapply every two hours while you are out.
General sun-care information, not medical advice. If you have a skin condition, a reaction to a product or a changing mole, talk to a dermatologist.
Let your phone remember for youPars Skin shows today’s UV for your city, logs your sunscreen and reminds you to reapply, staying quiet when UV is low. It also flags sun-sensitizing ingredients like retinol in your products. Private on your iPhone; not medical advice.
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