San Antonio, Texas UV Index
San Antonio UV index today — burn time, EPA scale, and sun-protection guidance
San Antonio, TX · UV Index right now
Skin burns in ~38 min
UV 3.5Moderate
A UV index of 3.5 means unprotected skin can begin to burn in roughly 25 minutes for the most sun-sensitive skin types (Fitzpatrick type I).
Peak UV today: 11:40 AM–3:40 PM
Estimated from today’s sunrise and sunset: UV is strongest in the two hours either side of solar noon (1:40 PM local time).
EPA UV Index scale
Current reading: UV 3.5 — Moderate.
Sun protection right now
- SPF & cover-up
- Wear SPF 30+ broad-spectrum sunscreen, a hat, and sunglasses; seek shade near midday.
- Reapply
- Reapply every two hours and after swimming or heavy sweating.
- Safe exposure
- Unprotected fair-to-medium (Fitzpatrick III) skin can begin to burn in about 38 minutes at this UV level. Sunscreen, shade, and cover-up extend that window.
EPA / WHO sun-safety guidance; type III skin baseline. Current band: Moderate.
Burn time by skin type
The current UV index is 3.5 (Moderate) — unprotected skin can begin to redden fastest for the fairest (Fitzpatrick type I) skin and slowest for the darkest (type VI).
See the full minutes-to-burn table for every UV level and all six skin types in the sunburn-time guide.
Sun protection for today's UV
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UV through the year in San Antonio
San Antonio’s subtropical latitude keeps the sun high for much of the year, and UV runs strongest in May, when the estimated clear-sky peak UV index reaches about 12 around solar noon. At that peak the noon sun reaches about 79° above the horizon. Each month below pairs the noon sun elevation with the estimated peak UV and how fast unprotected skin can begin to redden.
| Month | Noon sunelevation | Peak UVclear-sky est. | Type Imin to burn | Type IIImin to burn | Type VImin to burn |
|---|---|---|---|---|---|
| January | 39° | 4 | 22 | 33 | 111 |
| February | 48° | 6 | 15 | 22 | 74 |
| March | 58° | 8 | 11 | 17 | 56 |
| April | 70° | 11 | 8 | 12 | 40 |
| May | 79° | 12 | 7 | 11 | 37 |
| June | 84° | 12 | 7 | 11 | 37 |
| July | 82° | 12 | 7 | 11 | 37 |
| August | 75° | 11 | 8 | 12 | 40 |
| September | 64° | 10 | 9 | 13 | 44 |
| October | 52° | 7 | 13 | 19 | 63 |
| November | 42° | 5 | 18 | 27 | 89 |
| December | 37° | 4 | 22 | 33 | 111 |
Clear-sky estimate from sun angle and elevation — day-to-day clouds and ozone shift the real index up or down. Burn times are first-redness approximations for unprotected skin, not a safe-exposure budget.
Frequently asked
- When is UV strongest in San Antonio?
- In San Antonio the sun rides highest around May, when the estimated clear-sky peak UV index reaches about 12. Within any day it peaks near solar noon — roughly 10 a.m. to 4 p.m. local time. It is also stronger at higher elevation and near reflective surfaces like water, sand, and snow.
- Can you get sunburned on a cloudy day in San Antonio?
- Yes. Up to about 80% of UV radiation passes through clouds, so you can still burn in San Antonio on an overcast day. The WHO notes that thin or scattered cloud offers little protection — check the UV Index, not the sky.
UV & sun-safety guides
See how the UV Index works — including why clouds are no shield — plus evergreen guides to burn time, vitamin D, skin-cancer risk, and when UV is strongest, collected on the UV Index hub.
More for San Antonio
See the full San Antonio, TX weather forecast — hour-by-hour outlook, NOAA radar, satellite, and air quality.