Last updated: July 2, 2025
In Great Falls, understanding the UV Index is crucial for safeguarding your skin and overall health. The UV Index provides vital information about the sun's ultraviolet radiation levels, helping residents prevent sunburn and reduce long-term skin damage. Great Falls, with its BSk climate, experiences varying UV exposure throughout the day, peaking with a level of 9 around midday. By staying informed about UV levels, locals can enjoy outdoor activities while taking the necessary precautions to protect themselves from harmful effects. Whether you're out for a morning stroll or spending an afternoon in the sun, knowing the UV Index is key to enjoying the sunshine safely.
The UV Index reveals a dynamic day of sun exposure, peaking at 9 between 1 PM and 2 PM, indicating a notably high risk of harm from unprotected sun exposure. Early risers find the day starts with a comfortable 1 at 7 AM, gradually rising to 3 by 9 AM. By 11 AM, it reaches 7, encouraging outdoor enthusiasts to take precautions. The intensity continues to climb, soaring to its maximum at noon with an 8, before stabilizing at 9 during the early afternoon. As the sun begins its descent, the UV Index dips to 6 by 4 PM and further decreases to a 3 by 6 PM, finally settling at 1 as night falls. Enjoy the daylight, but remember to shield your skin 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 | 8 | very high | 15 min |
| 13:00 | 9 | 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 |