Last updated: June 2, 2025
Understanding the UV Index is crucial for residents and visitors in California—a state renowned for its sunny weather and outdoor lifestyle. The UV Index provides valuable information on the strength of ultraviolet (UV) radiation on a given day, enabling individuals to take proactive steps against sunburn and long-term skin damage. With California's climate producing consistently high UV levels, especially during midday hours when the index peaks at 10, awareness and preparedness are key to protecting your skin health. By understanding and monitoring the UV Index, you can enjoy the sunshine safely while minimizing the risks associated with excessive sun exposure.
The UV index begins its ascent at 07:00, starting at a gentle 1, then climbs gradually through the morning. By 10:00, it reaches a moderate 5, but from 11:00 onwards, the sun's intensity becomes pronounced, peaking at an impressive 10 between 13:00 and 14:00. After this zenith, the index dips to 8 at 15:00 and continues its decline, settling back to 2 by 18:00. As the day winds down into the evening, the UV index drops to a low 1 by 19:00, signaling a return to safer sun exposure levels. Enjoy the sunshine while staying protected during the high points!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 2 | low | 45 min |
| 09:00 | 3 | moderate | 30 min |
| 10:00 | 5 | moderate | 30 min |
| 11:00 | 7 | high | 25 min |
| 12:00 | 9 | very high | 15 min |
| 13:00 | 10 | very high | 15 min |
| 14:00 | 10 | very high | 15 min |
| 15:00 | 8 | very high | 15 min |
| 16:00 | 6 | high | 25 min |
| 17:00 | 4 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, UV exposure changes significantly, with high-risk months identified from April to September, when the UV Index reaches notably high levels of 9 to 10. During these months, burn times are critically reduced to just 15 minutes, requiring extra caution. March marks the transition to higher UV levels, with an index of 7 and a 25-minute burn time, while January and February begin with a moderate UV Index of 3 to 5 and longer burn times of 30 minutes. As we move into the fall, UV exposure decreases, dropping to 4 in November and 3 in December. Visitors and residents are advised to protect their skin by wearing sunscreen, protective clothing, and seeking shade, particularly during high-risk months, to minimize the risk of UV-related skin damage.
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 |
| California | 3 | 5 | 7 | 9 | 10 | 10 | 10 | 9 | 8 | 6 | 4 | 3 |
| Los Angeles UVI | 4 | 6 | 8 | 9 | 10 | 11 | 11 | 10 | 10 | 7 | 5 | 4 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |