Last updated: July 2, 2025
Understanding the UV Index is crucial for residents of Bristol, United States, as it serves as a vital indicator of potential sun exposure and associated risks. By keeping track of UV levels, you can protect yourself from harmful effects like sunburn and long-term skin damage. Bristol experiences a Cfa climate, characterized by warm summers with peak UV indexes soaring to 12 during midday hours, significantly heightening the risk of overexposure. Being informed about this index empowers you to take appropriate precautions, ensuring your skin remains healthy and protected year-round.
The UV Index throughout the day showcases a striking pattern, peaking at an impressive 12 by 1 PM. Beginning with a gentle start of 1 at 7 AM, the index steadily climbs, hitting 10 by 11 AM and reaching its zenith at 12 during the warmest hour. As the afternoon progresses, a decline occurs, with the index tapering off to 8 at 3 PM, and gradually dropping to 1 by 6 PM. This indicates that the highest UV exposure is between 11 AM and 1 PM, urging outdoor enthusiasts to take precautions during these 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 | 7 | high | 25 min |
| 11:00 | 10 | very high | 15 min |
| 12:00 | 11 | extreme | 10 min |
| 13:00 | 12 | 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 | 1 | low | 45 min |
| 19:00 | 1 | low | 45 min |
As the seasons change, so too does the UV Index, which significantly impacts exposure and burn time. From January's moderate UV Index of 5 with a burn time of 30 minutes, we enter a period of increasing risk; February through April sees a jump into the very high category, consistently reaching 8 to 10. The height of summer marks the peak danger, with May through July classified as extreme (UV Index 11 to 12), where just 10 minutes of exposure can lead to burns. August returns to an extreme level before tapering off in September and October to a very high index of 10 and 8 respectively. November and December bring a return to high and moderate levels, with more forgiving burn times of 25 and 30 minutes. Visitors and residents are advised to take necessary precautions, particularly during the high-risk months of February through October, wearing sunscreen, protective clothing, and seeking shade, especially during peak sunlight hours.
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 |
| Bristol | 5 | 8 | 9 | 10 | 11 | 11 | 12 | 11 | 10 | 8 | 6 | 4 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |