Last updated: June 2, 2025
Understanding the UV Index is crucial for residents and visitors in both China and the United States, as it serves as a vital tool for sunburn prevention and maintaining overall skin health. With China experiencing a diverse climate that features significant UV exposure, especially during peak hours, being aware of the UV levels can help you take necessary precautions. Notably, UV Index readings can soar to 11 by mid-afternoon, indicating extreme conditions that can pose serious risks to skin health. By staying informed about the UV Index, you can enjoy the outdoors while taking the essential steps to protect your skin from harmful ultraviolet rays.
The UV Index throughout the day reveals a striking pattern of solar intensity. Starting off low at 1 during the early hours of 07:00 and 08:00, the index takes a notable leap as the sun rises higher in the sky. By 09:00, it reaches 3, but the real surge hits at 10:00, soaring to 6. The peak occurs at 12:00, where it tops out at a blistering 11, followed closely by 12:00 with a maximum of 12, indicating an urgent need for sun protection. As the afternoon progresses, the index gradually declines but remains significant, hovering around 10 at 15:00 and sliding to 7 by 16:00. By 17:00, it drops to 4 and continues to fade into the evening hours, settling back at 1 by 19:00. This data underscores the importance of sun safety during peak hours, especially between 10:00 and 14:00 when UV exposure is at its highest.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 3 | moderate | 30 min |
| 10:00 | 6 | high | 25 min |
| 11:00 | 9 | very high | 15 min |
| 12:00 | 11 | extreme | 10 min |
| 13:00 | 12 | extreme | 10 min |
| 14:00 | 11 | extreme | 10 min |
| 15:00 | 10 | very high | 15 min |
| 16:00 | 7 | high | 25 min |
| 17:00 | 4 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
As the seasons change, so do the UV Index levels, significantly affecting the risk of skin damage from sun exposure. January and December have a moderate UV Index of 5, allowing for a burn time of 30 minutes. However, by February, the UV levels escalate to 8, marking the beginning of very high exposure with a reduced burn time of 15 minutes. The risk peaks in the summer months, particularly April through August, where the UV Index reaches a maximum of 12, classified as extreme, necessitating protective measures within just 10 minutes. September and October see a slight decline to very high levels of 10 and 9, respectively, while November cools to a high risk of 7 with a burn time of 25 minutes. Visitors and residents are advised to take precautions during the high-risk months of February to August, utilizing sunscreen, protective clothing, and seeking shade, particularly during peak sun hours, to minimize sun damage and maintain skin health.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chicago UVI | 3 | 4 | 6 | 8 | 9 | 10 | 10 | 9 | 8 | 6 | 4 | 2 |
| Brooklyn UVI | 3 | 5 | 6 | 8 | 10 | 10 | 9 | 9 | 8 | 6 | 4 | 2 |
| New York City UVI | 3 | 5 | 6 | 8 | 10 | 10 | 9 | 9 | 8 | 6 | 4 | 2 |
| Los Angeles UVI | 4 | 6 | 8 | 9 | 10 | 11 | 11 | 10 | 10 | 7 | 5 | 4 |
| China | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |