Last updated: July 2, 2025
Understanding the UV Index is crucial for residents of Helena, United States, where the high-altitude climate can lead to increased exposure to harmful ultraviolet rays. With typical midday UV levels reaching as high as 10, it's essential to be aware of the risks of sunburn and long-term skin health issues. By keeping an eye on the daily UV Index, you can take proactive measures to protect your skin while enjoying Helena's sunny days, ensuring safe outdoor activities and a healthier lifestyle in this beautiful BSk climate.
As the sun rises, the UV Index begins its steady ascent, starting at a mild 1 at 7:00 AM. By 8:00 AM, it reaches 2, hinting at the day ahead. As we approach mid-morning, the intensity climbs to 3 by 9:00 AM and then dramatically spikes to 5 at 10:00 AM. The real peak occurs between 12:00 PM and 2:00 PM, where the index soars to a whopping 10, indicating strong sun exposure. This midday intensity begins to taper off by 3:00 PM, as it drops to 9, and continues to slide through the late afternoon, ending the day at 1 by 7:00 PM. It's crucial to stay protected during those peak hours to enjoy the sun safely!
| 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 | 10 | very high | 15 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 |
Throughout the year, the UV Index experiences significant fluctuations, with the highest risk typically occurring from March to September. Visitors and residents should be particularly cautious during the high-risk months of April (UV Index 8), May (UV Index 9), June (UV Index 11), and July (UV Index 10), where the potential for skin damage is at its peak. During these months, burn times decrease dramatically, with the extreme risk in June allowing for only 10 minutes of unprotected sun exposure. As a guideline, it's advisable to wear protective clothing, apply broad-spectrum sunscreen, and seek shade during peak sun hours to minimize UV exposure. In contrast, October to February sees much lower UV levels, allowing for greater sun safety with recommended burn times ranging from 30 to 45 minutes.
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 |
| Helena | 3 | 4 | 6 | 8 | 9 | 11 | 10 | 9 | 8 | 5 | 3 | 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 |