August 13, 2026 · Hanoi, Vietnam
Capital1,431,270 people
See today's UV index in Hanoi 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 Hanoi's coordinates and updated daily.
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Daylight: sunrise 05:35 – sunset 18:29
Tomorrow: UV 6 at its peak around 11:00
The UV index in Hanoi peaks at 8 (very high) around 12:00 today. Sun protection is recommended between 08:22 and 15:14, while the index stays at 3 or above. Tomorrow the index is forecast to peak at 6 around 11:00.
| Time | UV index | Level |
|---|---|---|
| 05:00 | 0 | Low |
| 06:00 | 0.1 | Low |
| 07:00 | 0.8 | Low |
| 08:00 | 2.2 | Low |
| 09:00 | 4.4 | Moderate |
| 10:00 | 6.7 | High |
| 11:00 | 8.3 | Very high |
| 12:00 | 8.4 | Very high |
| 13:00 | 6.9 | High |
| 14:00 | 5.2 | Moderate |
| 15:00 | 3.4 | Moderate |
| 16:00 | 1.7 | Low |
| 17:00 | 0.5 | Low |
| 18:00 | 0.1 | Low |
| 19:00 | 0 | Low |
Hanoi lies at 21°N. The midday sun reaches 83.8° above the horizon in Hanoi today, and twice a year it passes straight overhead. Elevation is what sets the ceiling for UV, and over Hanoi 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. |