Last updated: May 3, 2025
Understanding the UV Index in Greybull, United States is crucial for maintaining your skin health and preventing sunburn, especially as this beautiful town experiences the dry climate typical of a BWk zone. With UV levels peaking at a noteworthy 10 around midday, awareness of these fluctuations can significantly reduce your risk of skin damage during sunny days. By keeping an eye on the UV Index, you can plan your outdoor activities safely and enjoy the stunning landscapes of Greybull while protecting your skin from harmful rays. Stay informed and make the most of your time under the sun!
The UV Index throughout the day paints a clear picture of sun intensity. Starting from a gentle 1 at 07:00, the UV levels gradually rise, peaking at an intense 10 by 13:00. This midday spike calls for caution as sun exposure increases significantly. As the afternoon progresses, from 14:00 to 15:00, the index slightly dips to 9 and 8, respectively, before gradually falling off to 6 at 16:00 and down to a mellow 1 by 19:00. For outdoor enthusiasts, the window between 11:00 and 13:00 is the time to enjoy the sun while remaining mindful of skin protection.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 2 | low | 45 min |
| 09:00 | 3 | moderate | 30 min |
| 10:00 | 5 | moderate | 30 min |
| 11:00 | 8 | very high | 15 min |
| 12:00 | 9 | very high | 15 min |
| 13:00 | 10 | very high | 15 min |
| 14:00 | 9 | very high | 15 min |
| 15:00 | 8 | very high | 15 min |
| 16:00 | 6 | high | 25 min |
| 17:00 | 4 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, ultraviolet (UV) radiation levels fluctuate significantly, impacting the risk of sunburn and skin damage. Higher UV Index values are observed from March to September, with the highest risks occurring in June and July (UV Index 11, extreme), where the recommended burn time is just 10 minutes. As spring transitions into summer, the UV Index escalates from a moderate level of 3 in January to very high levels of 8 in April and 10 in May. Visitors and residents are strongly advised to take precautions during these high-risk months, particularly from April through August, by using sunscreen, wearing protective clothing, and seeking shade during peak hours. In contrast, the UV Index decreases in the fall and winter, dropping to a low of 2 in December, where the burn time extends to 45 minutes. Remaining aware of these seasonal changes is essential for maintaining skin health year-round.
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 |
| Greybull | 3 | 5 | 6 | 8 | 10 | 11 | 11 | 10 | 9 | 6 | 4 | 2 |
| 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 |