Last updated: May 3, 2025
Understanding the UV Index is crucial for residents of Grass Valley, United States, where the warm Csa climate can lead to significant sun exposure risks. As UV levels peak during the day, especially reaching a maximum of 10 around midday, being aware of these levels is essential for preventing sunburn and maintaining skin health. With sunny skies prevalent in this picturesque region, knowing when to take precautions can help you enjoy outdoor activities while protecting yourself from harmful UV rays. Stay informed to safeguard your well-being and make the most of Grass Valley's beautiful sunshine!
At dawn, the UV Index starts at a mild 1 by 07:00, gradually climbing to 2 by 08:00 as the sun rises. The warmth intensifies, reaching 4 at 09:00 and peaking at a significant 10 between noon and 14:00, signaling the need for sun protection. As the afternoon rolls in, the index begins to dip, settling at 8 by 15:00 before tapering off further to 5 at 16:00. By the evening, the UV levels gracefully descend back to 2 at 18:00 and return to a safe 1 by 19:00, marking a day's journey through varying sun exposure. Be mindful of the midday sun, and stay protected during those peak hours!
| 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 | 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 | 5 | moderate | 30 min |
| 17:00 | 3 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
As the seasons change, so does the UV Index, reflecting the risk of UV exposure throughout the year. January and December see a moderate UV Index of 3, allowing for a burn time of 30 minutes. However, from February to March, the UV levels rise significantly, peaking at 11 during the summer months of June and July, categorized as extreme, with the shortest burn time of only 10 minutes in peak months like June. The high-risk months for UV exposure are clearly April to August, when the UV Index reaches very high to extreme levels. It is advisable for visitors and residents to take necessary precautions, such as wearing sunscreen, protective clothing, and limiting sun exposure during peak hours, especially from late spring to mid-summer. As fall approaches, the risk decreases, with the UV Index dropping back to moderate levels by November.
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 |
| Grass Valley | 3 | 5 | 7 | 8 | 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 |