Last updated: July 2, 2025
Understanding the UV Index is crucial for residents of Rapid City, where the combination of a Dfb climate and high altitudes can lead to significant sun exposure. The UV levels vary throughout the day, peaking between 11:00 AM and 2:00 PM, where they reach levels that can quickly result in sunburn and long-term skin health issues. By being aware of the UV Index, you can take proactive steps to protect your skin—such as wearing sunscreen and protective clothing—helping you enjoy the beautiful outdoor activities that Rapid City has to offer while maintaining your health and well-being.
This hour-by-hour UV Index data paints a clear picture of sun intensity throughout the day. At 07:00 and 08:00, the UV Index remains low at just 1, making it safe for outdoor activities. However, as the clock ticks toward mid-morning, the value climbs to 2 by 09:00. The sun's power peaks between 12:00 and 14:00, with a striking 8 and 9 respectively, indicating a high risk of harm from unprotected sun exposure. By 15:00, the index begins to decrease, dipping to 8, and continues its descent through the late afternoon and evening, reaching 5 at 17:00 and down to 2 by 19:00. Remember, during those mid-day hours, proper sun protection is essential to enjoy the outdoors safely!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 2 | low | 45 min |
| 10:00 | 4 | moderate | 30 min |
| 11:00 | 6 | 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 | 7 | high | 25 min |
| 17:00 | 5 | moderate | 30 min |
| 18:00 | 3 | moderate | 30 min |
| 19:00 | 2 | low | 45 min |
As the seasons change, the UV Index experiences notable fluctuations, influencing both visitor and resident safety. January and December boast a low UV Index of 2, allowing for extended exposure times of 45 minutes without significant risk. However, as we move into spring with February and March, the UV Index rises to 4 and 5 respectively, indicating a moderate risk with a burn time of just 30 minutes. The high-risk months arrive in April through August, with peak values of 9 and 10 during May and June, categorizing the exposure as very high and shortening safe sun exposure to as little as 15 minutes. September sees a slight decrease to a high index of 7, while October and November return to moderate levels. Visitors and residents should take precautionary measures during the higher UV months by seeking shade, wearing protective clothing, and using sunscreen regularly to minimize skin damage.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rapid City | 2 | 4 | 5 | 7 | 9 | 10 | 9 | 8 | 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 |