Last updated: July 2, 2025
Understanding the UV Index is crucial for residents of Bristol, United States, where the sunny climate can lead to significant sun exposure. As UV levels fluctuate throughout the day, awareness of these changes is essential for preventing sunburn and promoting long-term skin health. With typical midday UV indices reaching as high as 10, the risks associated with UV exposure can escalate quickly. By staying informed about the local UV forecast, you can enjoy the beautiful outdoor spaces of Bristol while also protecting your skin from harmful effects.
The UV Index starts off gentle in the early hours, peaking at 1 around 07:00 and 08:00. As the sun ascends, it gradually climbs to reach 2 by 09:00 and then surges to 4 by 10:00. A significant spike occurs around 11:00, peaking at 6, before reaching its zenith of 10 from 13:00 to 14:00—a crucial time for sun protection. As the afternoon wanes, the index begins to decline, tapering down to 7 at 16:00, then to 5 by 17:00. As the sun sets, it drops to 3 at 18:00, and finally sinks back to a safe 1 by 19:00, reminding us to be cautious in the midday sun while enjoying the warm daylight.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 2 | low | 45 min |
| 10:00 | 4 | moderate | 30 min |
| 11:00 | 6 | high | 25 min |
| 12:00 | 9 | very high | 15 min |
| 13:00 | 10 | very high | 15 min |
| 14:00 | 10 | very high | 15 min |
| 15:00 | 9 | very high | 15 min |
| 16:00 | 7 | high | 25 min |
| 17:00 | 5 | moderate | 30 min |
| 18:00 | 3 | moderate | 30 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, UV exposure varies significantly, with notable spikes during the summer months. January and February have a moderate UV Index of 3 and 5, respectively, allowing for around 30 minutes of sun exposure before burning. However, as spring approaches, March sees an increase to a high UV Index of 6, reducing burn time to 25 minutes. The intensity peaks in April and continues through August, where the UV Index reaches a very high level of 9 or 10, resulting in only 15 minutes of safe exposure. September starts to ease with an index of 8, followed by a return to high levels in October (6) and gradually decreasing to moderate levels in November and December (4 and 3, respectively). High-risk months for UV exposure are from April through September, during which residents and visitors are advised to take precautions such as using sunscreen, wearing protective clothing, and limiting sun exposure during peak 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 |
| Bristol | 3 | 5 | 6 | 9 | 9 | 10 | 10 | 9 | 8 | 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 |