Last updated: May 3, 2025
Understanding the UV Index is crucial for residents and visitors in Berkeley, United States, where sun exposure can quickly lead to skin damage. The UV levels can reach a peak of 10 during midday, indicating a very high risk of harm from unprotected sun exposure—especially important for sunburn prevention and long-term skin health. Given Berkeley's Mediterranean climate with warm, dry summers, awareness of these UV levels is essential for safe outdoor activities. Stay informed and protected to enjoy everything our beautiful city has to offer while keeping your skin safe!
As the sun rises, the UV Index begins its gradual ascent, starting at a mild 1 at 07:00. By 08:00, it reaches 2, indicating a low risk, perfect for morning strolls. The intensity picks up at 09:00, hitting 3, and then surges to 6 by 10:00. From 11:00 to 13:00, the index escalates dramatically, peaking at an intense 10, marking the hours when sun protection is crucial. The afternoon maintains this peak, with 10 persisting until 14:00. As the day progresses, the evening brings relief; the index drops to 8 at 15:00, and gradually declines to 3 by 17:00, and finally retreats to 1 by 19:00. This hourly data highlights the importance of seeking shade and using sunscreen during midday hours to ensure safety under the sun.
| 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 | 6 | high | 25 min |
| 11:00 | 8 | very high | 15 min |
| 12:00 | 10 | 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 | 3 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, UV index levels exhibit significant seasonal changes, with high-risk months primarily from March to August. During this period, the UV index peaks, reaching extreme levels of 11 in June and July, where the burn time is as low as 10 minutes. Visitors and residents should take precautionary measures during these months, seeking shade and using SPF protection to reduce the risk of sunburn and long-term skin damage. Levels start to moderate again from September to November, allowing for safer sun exposure. January and December present the least risk, with moderate UV index levels of 3, where exposure can be as long as 30 minutes without immediate harm. It's essential for everyone to remain vigilant and adjust their sun safety practices based on the UV index throughout the seasons.
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 |
| Berkeley | 3 | 5 | 8 | 9 | 10 | 11 | 11 | 10 | 9 | 7 | 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 |