Last updated: July 2, 2025
Understanding the UV Index is crucial for residents and visitors in Big Sky, United States, where the sun's rays can be deceptively strong due to the area's high elevation and unique Dfb climate. With UV levels peaking at 11 during midday hours, awareness of these fluctuations is vital for preventing sunburn and protecting skin health. As you enjoy the breathtaking landscapes and outdoor activities that Big Sky has to offer, keeping an eye on the UV Index can help safeguard against harmful effects of excessive sun exposure. Embrace the beauty of this mountain gem while being sun-smart!
The UV Index throughout the day reveals a notable trend, starting at a calm 1 at 7:00 AM and gradually climbing to its peak of 11 during the peak afternoon hours of 1:00 PM and 2:00 PM. As the sun climbs higher in the sky, the intensity of ultraviolet radiation increases, reaching a sharp rise to 10 by noon, signaling caution for outdoor activities. After the early afternoon, the index begins to decline, drifting down to 5 by 5:00 PM and tapering off to a gentle 1 by 7:00 PM. This data highlights the importance of sun safety, particularly during the mid-day hours when UV exposure is at its strongest. Remember to wear protective clothing and sunscreen when the UV Index rises!
| 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 | 10 | very high | 15 min |
| 13:00 | 11 | extreme | 10 min |
| 14:00 | 11 | extreme | 10 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 |
As the year progresses, the UV Index experiences noticeable changes, indicating varying levels of sun exposure risk. During the winter months, specifically January and February, UV levels remain moderate at 3 and 4 respectively, with a burn time of 30 minutes. However, spring ushers in a marked increase, with March reaching a high of 7 and April escalating to 9. The summer months of May, June, and July present extreme UV levels, peaking at 11 in May and June, while August begins to decline slightly but remains very high at 10. Autumn steps in gradually reducing risk, with September at 9 and October at 6. November and December boast lower levels of 4 and 2, indicating a return to moderate and low exposure risks. Visitors and residents should exercise caution, particularly during the high-risk months of April through August, where sun exposure can lead to severe skin damage in as little as 10 to 15 minutes. It is advisable to seek shade, wear protective clothing, and apply sunscreen consistently during these peak times to safeguard against harmful UV radiation.
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 |
| Big Sky | 3 | 4 | 7 | 9 | 11 | 12 | 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 |