Last updated: July 2, 2025
Understanding the UV Index is crucial for residents of Clark Fork, Idaho, where the mountainous terrain and clear skies can lead to significant sun exposure. As UV levels climb throughout the day, peaking at 9 around noon, awareness can play a vital role in preventing sunburn and maintaining long-term skin health. In this climate zone (Dsb), sunny days can be deceiving; while the temperatures may be mild, the UV radiation can still be harmful. Keeping an eye on the UV Index not only safeguards your skin but also ensures that your outdoor activities remain enjoyable and safe, no matter the season.
The UV Index throughout the day presents a clear pattern of intensity, peaking at midday. Starting from a mild level of 1 at 07:00, the index rises steadily, reaching 2 by 08:00. The real surge occurs between 09:00 and 13:00, where it escalates from 4 to a striking 9—the highest point of the day. As the afternoon unfolds, the intensity slightly declines to 7 at 15:00, before tapering off to 5 at 16:00. The evening sees a further decrease, settling back to 2 by 18:00 and returning to 1 at 19:00. For those enjoying outdoor activities, it’s essential to take precautions, especially during the peak hours from 11:00 to 14:00 when the UV rays are most potent.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 2 | low | 45 min |
| 09:00 | 4 | moderate | 30 min |
| 10:00 | 6 | high | 25 min |
| 11:00 | 8 | very high | 15 min |
| 12:00 | 9 | very high | 15 min |
| 13:00 | 9 | very high | 15 min |
| 14:00 | 9 | very high | 15 min |
| 15:00 | 7 | high | 25 min |
| 16:00 | 5 | moderate | 30 min |
| 17:00 | 3 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, the UV Index exhibits significant seasonal fluctuations, indicating varying levels of sun exposure risk. January and December present the lowest UV levels (Index 2), categorized as low, where individuals can safely be outside for up to 45 minutes without risk of sunburn. As we transition into February and March, UV indices increase to 4 and 6 respectively, marking them as moderate to high risk months, with recommended burn times decreasing to 30 and 25 minutes. The summer months of May to August reach their peak UV indices of 8 and 9, categorized as very high. During this time, even brief exposure can lead to burns within 15 minutes, making it imperative for visitors and residents to take extra precautions such as wearing sunscreen, protective clothing, and seeking shade. As autumn rolls in, the UV Index decreases again in September to 7 and stabilizes in the subsequent months, reminding everyone to remain vigilant even in moderate risk months like October and November with burn times extending to 30 minutes. Staying informed and proactive can significantly enhance sun safety throughout the year.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clark Fork | 2 | 4 | 6 | 7 | 8 | 9 | 9 | 9 | 7 | 4 | 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 |