Last updated: June 2, 2025
In Spearfish, South Dakota, being aware of the UV Index is crucial for protecting yourself from harmful solar radiation. With peak UV levels reaching a dangerous 11 during midday, understanding these fluctuations can help you prevent sunburn and maintain healthy skin. Spearfish, located in a Dfb climate zone, experiences significant UV exposure, particularly during the summer months. Whether you're enjoying outdoor activities or simply soaking up the sun, keeping an eye on the UV Index is essential for safeguarding your skin and overall well-being. Stay informed, stay safe!
The UV Index throughout the day exhibits a remarkable peak during the midday hours. Starting modestly at 1 by 7 AM, it gradually rises, reaching 4 by 9 AM. As the sun ascends, the intensity escalates sharply, hitting 7 at 10 AM and soaring to its highest point of 11 between 1 PM and 2 PM. This is a crucial time for sun protection, as the UV exposure is at its most intense. Fortunately, by late afternoon, relief comes as the index dips to 6 at 4 PM and plunges further to 1 by 7 PM, making those evening hours much safer for outdoor activities. Remember to safeguard 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 | 4 | moderate | 30 min |
| 10:00 | 7 | high | 25 min |
| 11:00 | 9 | very high | 15 min |
| 12:00 | 10 | very high | 15 min |
| 13:00 | 11 | extreme | 10 min |
| 14:00 | 10 | 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 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
As the seasons change, so do the UV index levels, which can significantly impact skin health. From January to February, the UV Index remains at a moderate level of 3 to 4, with a burn time of 30 minutes. However, March marks the onset of higher UV exposure with an increase to a 6 (high) and a burn time of just 25 minutes. The risk escalates sharply in April and May, where the UV Index peaks at 9 (very high) and burn times drop to 15 minutes. The highest levels occur during the summer months of June and July, reaching an extreme 11 with a mere 10 minutes of unprotected sun exposure before burning occurs. August and September remain risky with values of 10 and 8 respectively, necessitating vigilant sun protection measures. As temperatures cool in October, the UV Index diminishes to 5, falling to 3 in November and 2 in December, with longer burn times of 30 to 45 minutes. Visitors and residents should take extra precautions, especially from April to September, by using sunscreen, wearing protective clothing, and seeking shade during peak sun hours to mitigate the risk of skin damage.
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 |
| Spearfish | 3 | 4 | 6 | 9 | 9 | 11 | 11 | 10 | 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 |