Last updated: June 2, 2025
In Fullerton, California, staying informed about the UV Index is crucial to protecting your skin and overall health. With maximum UV levels peaking at 11 during midday, understanding these fluctuations can help you prevent sunburn and reduce long-term skin damage. Fullerton's BSk climate brings sunny days that can lead to increased UV exposure, making it essential for residents and visitors alike to be aware of these risks. Whether you're enjoying outdoor activities or simply gardening, knowing how to gauge UV levels ensures you can protect yourself from harmful rays while enjoying the beautiful Southern California sunshine.
The UV Index throughout the day follows a dynamic trajectory, peaking during midday hours. Early in the morning, at 7:00 AM, the index is a mere 1, indicating minimal risk. However, as the sun rises, the intensity escalates sharply, reaching 11 by 12:00 PM and 1:00 PM, signaling a high risk period for unprotected skin. By 3:00 PM, there's a noticeable decline to 8, and it continues to fall gently, arriving back at 1 by 7:00 PM. It’s crucial to stay protected during those peak hours, especially between 10:00 AM and 3:00 PM, when the sun's rays are the strongest.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 2 | low | 45 min |
| 09:00 | 4 | moderate | 30 min |
| 10:00 | 7 | high | 25 min |
| 11:00 | 9 | very high | 15 min |
| 12:00 | 11 | extreme | 10 min |
| 13:00 | 11 | extreme | 10 min |
| 14:00 | 10 | very high | 15 min |
| 15:00 | 8 | very high | 15 min |
| 16:00 | 5 | moderate | 30 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 fluctuate significantly, reflecting seasonal changes in sun exposure. January and December exhibit moderate UV levels (Index 4), with a burn time of 30 minutes. As spring arrives, February escalates to a high UV Index of 6 with a reduced burn time of 25 minutes. The risk peaks in March and April, hitting a very high UV Index of 8 and 10 respectively, with critical burn times of just 15 minutes. The summer months of June and July show the highest UV Index at 11, categorized as extreme, where even a brief 10-minute exposure can lead to burns. Although August and September remain very high, it’s crucial to remain vigilant. As UV levels taper off in October and November, a moderate level of risk is present again. Residents and visitors are advised to protect themselves with sunscreen, hats, and sunglasses, especially from March to September when UV exposure can be particularly harmful.
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 |
| Fullerton | 4 | 6 | 8 | 10 | 10 | 11 | 11 | 10 | 10 | 7 | 5 | 4 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |