Last updated: June 2, 2025
Understanding the UV Index is crucial for residents of Livermore, California, where sunny days are frequent and UV radiation levels can soar. With peak UV Index values reaching as high as 11 in the midday sun, it’s essential to be aware of UV levels to prevent sunburn and protect your skin health. Livermore’s Cfa climate provides ample opportunity for outdoor activities, but also presents heightened risks for UV exposure, especially during late morning and early afternoon hours. By staying informed about the UV Index, you can enjoy the beautiful California weather while safeguarding your well-being.
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 display significant seasonal variation, with notable peaks during the spring and summer months. From January (UV Index 3) to March (UV Index 7), exposure remains moderate to high, but by April and May (UV Index 10), it escalates to a very high category, necessitating increased sun protection. The most critical periods, with an extreme UV index of 11, occur in June, reminding visitors and residents to exercise extreme caution and limit sun exposure to just 10 minutes. This trend continues into July and August with very high levels, tapering off slightly in September (UV Index 9), before returning to high levels in October (UV Index 7). Residents and visitors should prioritize sun safety during the high-risk months of April to September, using sunscreen, wearing protective clothing, and seeking shade to minimize UV exposure. In contrast, November and December see a welcome decrease with a moderate UV index, allowing for more comfortable outdoor activities.
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 |
| Livermore | 3 | 6 | 7 | 10 | 10 | 11 | 10 | 10 | 9 | 7 | 5 | 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 |