Last updated: June 2, 2025
Understanding the UV Index is crucial for residents and visitors of Si'an, China, where the climate often brings hot and humid conditions characterized by high sun exposure. With peak UV levels reaching 10 around midday, being aware of these readings is essential for preventing sunburn and protecting skin health. Knowledge of UV levels helps people take preemptive measures, such as applying sunscreen or seeking shade, especially during the summer months when the risk of harmful UV radiation is significantly elevated. By staying informed about the UV Index in Si'an, you can enjoy the outdoors while safeguarding your skin from long-term damage.
The UV Index paints a vivid picture of the sun’s intensity throughout the day. At sunrise (07:00), the index starts modestly at 2, but by 08:00, it rises to a comfortable 4. The sun gains strength, with readings escalating to 6 by 09:00. The peak arrives at 11:00 and 12:00, where the index reaches a striking 10—a clear signal to seek shade or apply sunscreen! As the afternoon progresses, we see a decline; the UV Index drops to 9 at 13:00 and gradually decreases to 5 by 15:00. The late afternoon brings a gentle taper off to 3 by 16:00, before plummeting to 1 by 17:00 and finally settling at 0 as evening descends (19:00). Stay sun-smart and enjoy the daylight safely!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 2 | low | 45 min |
| 08:00 | 4 | moderate | 30 min |
| 09:00 | 6 | high | 25 min |
| 10:00 | 9 | very high | 15 min |
| 11:00 | 10 | very high | 15 min |
| 12:00 | 10 | very high | 15 min |
| 13:00 | 9 | very high | 15 min |
| 14:00 | 7 | high | 25 min |
| 15:00 | 5 | moderate | 30 min |
| 16:00 | 3 | moderate | 30 min |
| 17:00 | 1 | low | 45 min |
| 18:00 | 1 | low | 45 min |
| 19:00 | 0 | low | 45 min |
As the seasons change, so do UV levels, significantly impacting sun safety. January starts with a UV Index of 4, categorized as moderate, allowing for approximately 30 minutes of unprotected sun exposure. This rises sharply through February and March, reaching 6 (high) and 8 (very high), respectively, with burn times dropping to 25 and 15 minutes. The peak months, July and August, see an extreme UV Index of 11, where the burn time is reduced to a mere 10 minutes. As fall approaches, the UV Index decreases to 10 in September, then 8 in October. By November and December, the UV Index returns to 6 and 4, respectively, allowing for safer exposure times of 25 and 30 minutes. Visitors and residents should remain vigilant during the high-risk months of March to October, especially in the peak summer months, and take appropriate precautions such as wearing sunscreen, protective clothing, and seeking shade during peak hours.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Beijing UVI | 2 | 3 | 5 | 8 | 9 | 9 | 10 | 9 | 7 | 6 | 4 | 2 |
| Si'an | 4 | 6 | 8 | 10 | 10 | 10 | 11 | 11 | 10 | 8 | 6 | 4 |
| Chengdu UVI | 5 | 6 | 8 | 10 | 12 | 11 | 11 | 10 | 11 | 8 | 6 | 4 |
| Shanghai UVI | 5 | 6 | 8 | 10 | 10 | 11 | 12 | 11 | 11 | 8 | 6 | 4 |
| Guangzhou UVI | 7 | 9 | 11 | 12 | 13 | 13 | 13 | 12 | 11 | 10 | 9 | 7 |
| Shenzhen UVI | 7 | 10 | 12 | 12 | 14 | 13 | 13 | 13 | 12 | 11 | 9 | 7 |