Last updated: July 2, 2025
The UV Index in Berkeley, United States is a crucial tool for residents to protect their skin from harmful ultraviolet radiation. Understanding the UV levels throughout the day is essential to prevent sunburn and promote long-term skin health, especially during those peak hours when the index reaches an impressive 11 around noon. With Berkeley's Csb climate, which features mild, wet winters and dry summers, local residents should be aware of increased UV exposure risks, particularly in the summer months when the sun's rays can be most intense. Staying informed about the UV Index not only helps you enjoy the sunny outdoors safely but also fosters overall well-being in this vibrant Californian city.
As the sun rises, the UV Index starts off gently at 1 by 7:00 AM, gradually climbing as the day progresses. By 10:00 AM, it reaches 6, signaling a notable increase in solar radiation. The intensity peaks at 12:00 PM with a striking 10 and continues to soar to a maximum of 11 at 1:00 PM, marking the hour of greatest exposure. As the afternoon unfolds, the index begins to taper off—dropping to 10 at 2:00 PM and 8 by 3:00 PM. By late afternoon, the UV Index gracefully descends to 4 at 5:00 PM, settling back to 2 by 6:00 PM and finally returning to a gentle 1 by 7:00 PM. This highlights the importance of sun protection during mid-day when UV rays are at their most intense.
| 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 | 11 | extreme | 10 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 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 |