August 13, 2026 · Houston, USA
2,296,224 people
See today's UV index in Houston hour by hour below. The UV index shows how strong the sun's ultraviolet radiation is — the higher the number, the faster skin can burn. Values are calculated for Houston's coordinates and updated daily.
UV has dropped for today
Protection windowClear sky
Daylight: sunrise 06:49 – sunset 20:06
Tomorrow: UV 9 at its peak around 14:00
The UV index in Houston peaks at 9 (very high) around 13:00 today. Sun protection is recommended between 09:36 and 16:51, while the index stays at 3 or above. Cloud cover is damping the peak by roughly 16% compared with a clear sky. Tomorrow the index is forecast to peak at 9 around 14:00.
| Time | UV index | Level |
|---|---|---|
| 06:00 | 0 | Low |
| 07:00 | 0.1 | Low |
| 08:00 | 0.5 | Low |
| 09:00 | 1.8 | Low |
| 10:00 | 3.8 | Moderate |
| 11:00 | 5.9 | Moderate |
| 12:00 | 7.7 | High |
| 13:00 | 8.6 | Very high |
| 14:00 | 8.4 | Very high |
| 15:00 | 6.9 | High |
| 16:00 | 4.8 | Moderate |
| 17:00 | 2.7 | Low |
| 18:00 | 1.2 | Low |
| 19:00 | 0.3 | Low |
| 20:00 | 0 | Low |
| 21:00 | 0 | Low |
Houston lies at 30°N. The midday sun reaches 74.9° above the horizon in Houston today, against a yearly ceiling of 83.7°. Elevation is what sets the ceiling for UV, and over Houston it is so steep that the rays take the shortest possible path through the atmosphere, and the index can reach extreme values.
The UV index is an international scale describing the strength of the sun's ultraviolet radiation at ground level. It starts at 0 and is effectively open-ended — at mid-latitudes it rarely exceeds 8, while in the tropics and high in the mountains it can pass 11. The higher the number, the less time it takes to get sunburnt.
The UV index depends mainly on how high the sun is in the sky. That is why it peaks around solar noon and is greatest in summer near the longest day of the year. Clouds, ozone, altitude and reflection from snow or water also affect the value.
| UV index | Level | Recommendation |
|---|---|---|
| 0–2 | Low | No special protection needed. |
| 3–5 | Moderate | Use sunscreen (SPF 30+), seek shade around midday. |
| 6–7 | High | Sunscreen, hat and sunglasses. Avoid the sun 12:00–15:00. |
| 8–10 | Very high | Extra protection. Limit midday sun exposure. |
| 11+ | Extreme | Avoid the sun at midday. Full protection required. |