View All Articles

The Ultraviolet (UV) Index Scale

The Ultraviolet Radiation Scale or UV Index scale represents the risk of sun exposure and steps to protect yourself from UV radiation are listed below  
Ultraviolet (UV) Index Scale

Ultraviolet (UV) Index Scale

UV Index 0 to 2 (Low)

A UV Index reading of 0 to 2 means low danger from the sun’s UV rays for the average person.
  • Wear sunglasses on bright days.
  • If you burn easily, cover up and use broad spectrum SPF 30+ sunscreen.
  • Watch out for bright surfaces, like sand, water and snow, which reflect UV and increase exposure.

UV Index 3 to 5 (Moderate)

A UV Index reading of 3 to 5 means moderate risk of harm from unprotected sun exposure.
  • Stay in shade near midday when the sun is strongest.
  • If outdoors, wear protective clothing, a wide-brimmed hat, and UV-blocking sunglasses.
  • Generously apply broad spectrum SPF 30+ sunscreen every 2 hours, even on cloudy days, and after swimming or sweating.
  • Watch out for bright surfaces, like sand, water and snow, which reflect UV and increase exposure.

UV Index 6 to 7 (High)

A UV Index reading of 6 to 7 means high risk of harm from unprotected sun exposure. Protection against skin and eye damage is needed.
  • Reduce time in the sun between 10 a.m. and 4 p.m.
  • If outdoors, seek shade and wear protective clothing, a wide-brimmed hat, and UV-blocking sunglasses.
  • Generously apply broad spectrum SPF 30+ sunscreen every 2 hours, even on cloudy days, and after swimming or sweating.
  • Watch out for bright surfaces, like sand, water and snow, which reflect UV and increase exposure.

UV Index 7 to 10 (Very High)

A UV Index reading of 8 to 10 means very high risk of harm from unprotected sun exposure. Take extra precautions because unprotected skin and eyes will be damaged and can burn quickly.
  • Minimize sun exposure between 10 a.m. and 4 p.m.
  • If outdoors, seek shade and wear protective clothing, a wide-brimmed hat, and UV-blocking sunglasses.
  • Generously apply broad spectrum SPF 30+ sunscreen every 2 hours, even on cloudy days, and after swimming or sweating.
  • Watch out for bright surfaces, like sand, water and snow, which reflect UV and increase exposure.

UV Index11+ (Extreme)

A UV Index reading of 11 or more means extreme risk of harm from unprotected sun exposure. Take all precautions because unprotected skin and eyes can burn in minutes.
  • Try to avoid sun exposure between 10 a.m. and 4 p.m.
  • If outdoors, seek shade and wear protective clothing, a wide-brimmed hat, and UV-blocking sunglasses.
  • Generously apply broad spectrum SPF 30+ sunscreen every 2 hours, even on cloudy days, and after swimming or sweating.
  • Watch out for bright surfaces, like sand, water and snow, which reflect UV and increase exposure.

The Shaddow Rule

An easy way to tell how much UV exposure you are getting is to look for your shadow:
  • If your shadow is taller than you are (in the early morning and late afternoon), your UV exposure is likely to be lower.
  • If your shadow is shorter than you are (around midday), you are being exposed to higher levels of UV radiation. Seek shade and protect your skin and eyes.
Related Information on Ultraviolet (UV) Radiation:
  1. What is Ultraviolet (UV) Radiation?
  2. The Ultraviolet (UV) Index Scale
  3. Download EPA UV Facts Sheet on Ultraviolet (UV) Radiation
This entry was posted in Basic Meteorology and tagged , , , , , , , , , , , . Bookmark the permalink.

Leave a Reply

Read More

Oklahoma severe thunderstorms: SPC Enhanced Risk map for Oklahoma City, Tulsa and Enid on November 2, 2026, with Slight and Marginal Risk across the southern and central Plains

Oklahoma Severe Thunderstorms: SPC Enhanced Risk for Oklahoma City, Tulsa and Enid on November 2, 2026

Oklahoma severe thunderstorms are the headline threat on Monday, November 2, 2026, after the NOAA Storm Prediction Center placed north-central Oklahoma and south-central Kansas under an Enhanced Risk, the third of five severe categories (level 3…

Read More

iNWS decommissioned: NWS alerts by text, email and voice continue with iAlert

iNWS Decommissioned: How Emergency Managers Can Keep NWS Alerts Coming

With iNWS decommissioned as of October 22, 2026, emergency managers, county agencies and media partners lost the website that managed their NWS text and email alerts. The National Weather Service took the site down effective immediately,…

Read More

Arizona severe thunderstorms: SPC Day 1 outlook map with an Enhanced Risk over Flagstaff and Prescott, October 21, 2026

Arizona Severe Thunderstorms: SPC Enhanced Risk for Flagstaff and Prescott on October 21, 2026

Arizona severe thunderstorms are the headline threat in the NOAA Storm Prediction Center's updated Day 1 Convective Outlook for Wednesday, October 21, 2026, issued 12:30 UTC (5:30 am MST / 8:30 am EDT). The outlook places…

Read More

Leave a Reply