Last updated: May 3, 2025
Understanding the UV Index is crucial for residents of Helena, United States, where sunshine can be both a delight and a potential hazard. As UV levels peak at times, notably reaching 11 around noon, being aware of these readings is essential for preventing sunburn and promoting long-term skin health. Located in a Cfa climate zone, Helena experiences varied exposure risks, particularly during the summer months when the sun’s intensity is at its highest. By staying informed about UV Index levels, you can enjoy your outdoor activities while protecting your skin from harmful UV rays.
Throughout the day, the UV Index experiences a dramatic increase, peaking at 11 between noon and 1 PM, indicating a very high level of solar radiation. Early risers will notice a gentle start, with a UV Index of just 1 at 7 AM, gradually climbing to 4 by 9 AM. As the sun reaches its zenith, values soar to 9 at 11 AM, signaling it's time to take precautions. After the peak, the UV Index begins to decline, dropping to 10 at 2 PM, then tapering off to 3 by 5 PM and resting back down to 1 by 6 PM. Staying protected in the midday sun is crucial for skin safety during these hours!
| 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 | 7 | high | 25 min |
| 11:00 | 9 | very high | 15 min |
| 12:00 | 11 | extreme | 10 min |
| 13:00 | 11 | extreme | 10 min |
| 14:00 | 10 | very high | 15 min |
| 15:00 | 7 | high | 25 min |
| 16:00 | 5 | moderate | 30 min |
| 17:00 | 3 | moderate | 30 min |
| 18:00 | 1 | low | 45 min |
| 19:00 | 1 | low | 45 min |
As the seasons change, so does the UV Index, which significantly impacts exposure levels throughout the year. January starts with a moderate UV Index of 4, allowing for a burn time of 30 minutes. However, February ramps up to a high index of 7, with a reduced burn time of 25 minutes. The peak months, from March through August, experience extreme UV levels, particularly in May and June, where the UV Index reaches 11 and burn times shrink to just 10 minutes. September and October see a slight decrease, yet still maintain a very high index of 9 and 8, respectively. The year concludes with lower levels in November and December. Visitors and residents should take special care during the high-risk months from March to August, ensuring proper sun protection measures, such as wearing sunscreen, hats, and protective clothing, to mitigate the risk of UV-related harm.
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 |
| Los Angeles UVI | 4 | 6 | 8 | 9 | 10 | 11 | 11 | 10 | 10 | 7 | 5 | 4 |
| Helena | 4 | 7 | 8 | 10 | 11 | 11 | 11 | 11 | 9 | 8 | 6 | 4 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |