Last updated: May 3, 2025
Understanding the UV Index in Petaluma, United States is crucial for safeguarding your skin and overall health. With exposure to harmful ultraviolet rays peaking during the late morning and early afternoon—reaching levels as high as 10—awareness of UV levels can help prevent painful sunburns and long-term skin damage. Petaluma's coastal climate (Csb) brings moderate temperatures, but even on seemingly pleasant days, the risk of UV exposure can be significant. Stay informed and protect yourself by checking the UV Index regularly, ensuring you enjoy the sunshine 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 exposure varies significantly, with high-risk months typically occurring from March to September. During these months, particularly in April through July, the UV index reaches notably high levels, peaking at 11, which indicates extreme exposure risks and a quick burn time of just 10 minutes. As the seasons shift, visitors and residents should be particularly vigilant from May to August, when protective measures such as sunscreen, hats, and seeking shade are essential to prevent skin damage. In contrast, January, November, and December present a moderate UV index of 3-4, allowing for longer burn times of 30 minutes, though sunscreen should still be applied. Staying informed about these UV changes can help ensure safe outdoor activities year-round.
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 |
| Petaluma | 3 | 5 | 7 | 9 | 10 | 11 | 11 | 10 | 9 | 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 |