Quick answer: Under clear skies, peak UV in Knoxville today reaches roughly index 12 around solar noon, with the sun 65° above the horizon. Cloud cover can cut that by 20–50 %; protection is advised from index 3 upwards.
Conditions on this page are recalculated from the latest forecast every time it is opened, for the current date in the location's own time zone. Showing .
The UV index in Knoxville, USA can vary dramatically through the day, especially in summer or at high latitude. This page shows today's UV index hour-by-hour, calls out the peak UV time, and tells you how strong sun protection needs to be at each hour. We use the World Health Organization UV index scale (0–11+) so values are directly comparable to UV forecasts you might see in apps or on the news. The page also shows tomorrow and the rest of the week, so you can plan beach days, hikes, sightseeing or sports in Knoxville around safer UV windows. Sun safety advice is tailored to the actual UV reading: at low UV you need little protection, while at very high UV in Knoxville you should reduce time outdoors during peak hours. This is especially relevant for fair-skinned visitors and for outdoor activities at altitude.
UV strength follows solar elevation almost directly. With the sun at 65° at solar noon in August, the clear-sky UV index in Knoxville peaks near 12. Anything from 3 upwards means sunscreen and shade during the middle of the day; 8 and above means limiting exposure between roughly 10:00 and 16:00 local time.
Daylight, midday sun angle and golden-hour length below are calculated for Knoxville's own coordinates (35.96° N, 83.92° W) on the 15th of each month.
| Month | Daylight | Sun at solar noon | Golden hour |
|---|---|---|---|
| January | 10 h 0 min | 33° | 56 min |
| February | 10 h 48 min | 41° | 52 min |
| March | 11 h 54 min | 51° | 50 min |
| April | 13 h 6 min | 63° | 50 min |
| May | 14 h 6 min | 73° | 54 min |
| June | 14 h 36 min | 77° | 56 min |
| July | 14 h 24 min | 76° | 55 min |
| August | 13 h 30 min | 68° | 52 min |
| September | 12 h 24 min | 56° | 49 min |
| October | 11 h 12 min | 44° | 51 min |
| November | 10 h 12 min | 35° | 54 min |
| December | 9 h 42 min | 31° | 57 min |
Scores are capped by dealbreakers — heavy rain, dangerous wind, thick fog or hazardous UV pull a day down no matter how pleasant the rest of the numbers look. Forecast data is Open-Meteo; solar and lunar values are computed for Knoxville's own coordinates and time zone. Full details on the methodology page.