UV Index Today
See the UV index right now for your location, an hour-by-hour UV forecast for today and the next two days, the peak time and the hours when sun protection is recommended (UV 3 and above). Colors follow the international WHO UV index scale.
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Hourly UV index
Low 0-2Moderate 3-5High 6-7Very high 8-10Extreme 11+Clear sky
How to use the UV Index Today
- Pick your place: the page opens on your last place (or New York). Search a city or postcode, type lat, lon, or press Use my location.
- Check the UV now: the big colored card shows the current UV index and its category on the WHO scale.
- Plan your day: read the peak time and the protection window, the hours when the UV index is 3 or higher.
- Look ahead: switch between Today, Tomorrow and the next day, and hover or tap the bars to see each hour.
- Save it: copy a short UV summary or download the hourly forecast as a CSV file.
The UV index scale
The UV index was standardized by the World Health Organization, the World Meteorological Organization and the UN Environment Programme so that the same number means the same risk everywhere. It is calculated from the solar spectrum weighted by how strongly each wavelength reddens skin (the erythemal action spectrum): UV index = erythemal irradiance in W/m² × 40.
| UV index | Category | Color | Recommended protection |
|---|---|---|---|
| 0 to 2 | Low | Green | Little protection needed; sunglasses on bright days, extra care on snow and water |
| 3 to 5 | Moderate | Yellow | Shade near midday, hat, sunglasses, SPF 30+ sunscreen |
| 6 to 7 | High | Orange | Reduce time in the sun during the middle of the day; full protection |
| 8 to 10 | Very high | Red | Extra protection; unprotected skin and eyes can burn quickly |
| 11+ | Extreme | Violet | Avoid the midday sun where possible; all precautions |
What raises or lowers the UV index
- Sun angle: the higher the sun, the shorter the path through the atmosphere. UV peaks around solar noon and in late spring and summer; in the tropics it often reaches 11+ year-round.
- Latitude: a summer noon UV index is typically 6 to 8 in New York or London, 9 to 11 in Florida or southern Europe and can exceed 12 in Hawaii, northern Australia or high mountains.
- Ozone: the ozone layer absorbs most UV-B. Thinner ozone (for example in the Southern Hemisphere spring) means a higher index.
- Clouds: thick overcast can cut UV by more than half, but thin or scattered clouds block very little. Compare the bars (forecast) with the clear-sky line on the chart.
- Altitude and surfaces: about +10% per 1,000 m of elevation; snow, water and sand reflect extra UV onto skin and eyes.
Tips for using the forecast
- Schedule outdoor exercise, yard work or kids' play outside the protection window when you can.
- The shadow rule is a handy check: if your shadow is shorter than you are, UV is usually high.
- Sunscreen wears off: reapply about every 2 hours and after swimming or sweating, whatever the SPF.
Frequently asked questions
What does the UV index number mean?
The UV index is an international standard (WHO, WMO and UNEP) that measures the strength of sunburn-producing ultraviolet radiation at the ground. Each unit equals 25 milliwatts per square meter of skin-weighted UV. 0 to 2 is low, 3 to 5 moderate, 6 to 7 high, 8 to 10 very high and 11 or more extreme.
At what UV index do I need sunscreen?
Health agencies such as the WHO and the US EPA recommend sun protection when the UV index is 3 or higher: shade around midday, clothing, a hat, sunglasses and a broad-spectrum SPF 30+ sunscreen. The tool shows the exact hours when the forecast UV index is 3 or more as the protection window.
What time is the UV index highest?
UV is strongest when the sun is highest in the sky, around solar noon. That is usually between 11 am and 2 pm standard time, or roughly 12 pm to 3 pm during daylight saving time, depending on where you are inside your time zone. The Peak UV card shows the forecast peak hour for your exact location.
Can you get sunburned on a cloudy day?
Yes. Thin or broken clouds let most UV through, and up to about 80% can pass through light cloud cover. Broken clouds can even raise UV briefly by reflecting it. That is why the tool shows the clear-sky UV as well: it is the level you would get when the clouds clear.
Why is the UV index different from my weather app?
Apps use different forecast models and update times, and some show the daily maximum while others show the current hour. This tool uses the Open-Meteo UV forecast, which accounts for forecast clouds and the ozone layer, for the nearest model grid point. Differences of 1 index point are normal.
Does altitude, snow or water change UV exposure?
Yes. UV intensity rises by roughly 10% for every 1,000 m (3,300 ft) of altitude, fresh snow reflects up to 80% of UV, sea foam about 25% and dry sand about 15%. On ski slopes, beaches and boats the effective exposure can be much higher than the index alone suggests.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.