Last updated: July 2, 2025
Understanding the UV Index in Thornton, United States is crucial for safeguarding your skin and overall health. With the sun's rays intensifying throughout the day, particularly during peak hours when the UV Index can soar to 12, it's vital to be aware of the UV levels to prevent sunburn and long-term skin damage. Given Thornton's Cfa climate, which features warm summers with considerable UV exposure, residents and visitors alike should stay informed about these levels to enjoy outdoor activities safely. Embrace the sun wisely by recognizing the importance of UV Index awareness in protecting your skin health!
The day begins gently with a UV Index of 1 at both 07:00 and 08:00, indicating minimal sun exposure. However, as the clock strikes 09:00, the index rises to 3, signifying a gradual increase in UV intensity. By 10:00, it reaches 5, and the sun takes center stage at 11:00 with a striking 8. The peak arrives at 12:00, soaring to an impressive 10, and continues to climb, hitting its pinnacle with a dazzling 12 at 13:00. As the afternoon unfolds, values begin a slow descent: 11 at 14:00, 10 at 15:00, and then dropping to 7 by 16:00. The evening brings relief, with the index tapering down to 4 at 17:00, 2 at 18:00, and finally returning to a safe 1 by 19:00. Remember to stay protected during those peak hours!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 3 | moderate | 30 min |
| 10:00 | 5 | moderate | 30 min |
| 11:00 | 8 | very high | 15 min |
| 12:00 | 10 | very high | 15 min |
| 13:00 | 12 | extreme | 10 min |
| 14:00 | 11 | extreme | 10 min |
| 15:00 | 10 | very high | 15 min |
| 16:00 | 7 | high | 25 min |
| 17:00 | 4 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
The UV Index varies significantly throughout the year, indicating changes in sun exposure risk. Notably, March through September presents the highest risk, peaking in July with an intense UV Index of 12, categorized as extreme, and a burn time of just 10 minutes. April, May, June, and August maintain similarly high levels, all falling under the extreme category. The high-risk months where caution is particularly warranted are February through October, with March to August being critical for sun safety. Residents and visitors should take precautions during these months, such as wearing protective clothing, using broad-spectrum sunscreen, and seeking shade, particularly during peak hours of sunlight, to minimize the risk of skin damage. As the seasons transition, January and December demonstrate lower levels (UV Index 4), with moderate exposure risk, allowing for more lenient 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 |
| Los Angeles UVI | 4 | 6 | 8 | 9 | 10 | 11 | 11 | 10 | 10 | 7 | 5 | 4 |
| Thornton | 4 | 7 | 8 | 11 | 11 | 11 | 12 | 11 | 10 | 8 | 6 | 4 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |