Last updated: June 2, 2025
Understanding the UV Index is essential for residents of Great Falls, Montana, where the high-desert climate can lead to significant ultraviolet radiation exposure. Awareness of UV levels not only aids in preventing painful sunburns but also plays a crucial role in maintaining long-term skin health. As the sunshine peaks around midday with indices soaring to 10, it's vital to recognize the risks associated with outdoor activities during these hours, particularly in Great Falls, where the BSk climate can contribute to higher UV exposure even on seemingly mild days. Stay informed and protect your skin!
As the sun climbs higher in the sky, the UV Index reaches its peak intensity between 12:00 PM and 1:00 PM, with a striking value of 10—a clear indication that sun protection is essential during this time. The day starts off gently, with a maximum index of 1 at 7:00 AM, gradually rising to a moderate level of 3 by 9:00 AM. By 11:00 AM, we hit 7, and the intensity continues to soar, peaking at 9 around 12:00 PM. However, as the afternoon wanes, the index starts to decline, dropping to 8 at 3:00 PM, and cooling off to 4 by 5:00 PM. As evening approaches, the UV levels return to a milder 1 by 7:00 PM, marking the end of a sun-soaked day. Enjoy the sunshine, but don't forget to stay protected during those peak hours!
| 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 | 7 | high | 25 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 | 3 | moderate | 30 min |
| 19:00 | 1 | low | 45 min |
The UV Index exhibits significant seasonal changes, with the highest levels occurring from April to August. During this peak period, particularly in May and June, the UV Index reaches 10 and 9, categorized as very high, indicating a burn time of only 15 minutes. Visitors and residents should pay special attention to April through August as these months represent the highest risk for UV exposure. In contrast, January, December, and November show much lower UV levels, categorized as low or moderate, allowing for longer exposure times of 30 to 45 minutes without significant risk. It is advisable for individuals to seek shade, wear protective clothing, and apply sunscreen, particularly during the high-risk months from April to August, to minimize the chance of skin damage.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Great Falls | 2 | 4 | 5 | 7 | 9 | 10 | 9 | 9 | 7 | 5 | 3 | 2 |
| 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 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |