Last updated: May 3, 2025
In Tonto Basin, understanding the UV Index is crucial for safeguarding your skin health against the region's high sun exposure. With peak UV levels reaching a dangerous 12 around noon, awareness of the daily UV index can help residents and visitors alike prevent painful sunburn and long-term skin damage. Tonto Basin’s semi-arid climate not only means plenty of sunshine but also increased risks of overexposure, particularly during the hotter hours of the day. By monitoring UV levels, you can enjoy the beautiful outdoors while taking the necessary precautions to protect your skin.
As the sun rises, the UV Index begins its ascent, starting at a mild 1 at 07:00. By 08:00, it increases to a moderate 3, but the real surge comes just before noon. The index peaks at an intense 12 during the midday hours, specifically at 12:00, urging sun protection for those outdoors. Following this high, a gradual decrease occurs, with the values declining to 10 by 14:00, then tapering off to 7 at 15:00. As the day wanes, the UV intensity drops significantly, falling to 1 by 19:00, signifying a much safer period for sun exposure. This hourly UVI cycle illustrates a clear pattern: the importance of seeking shade and wearing sunscreen during the peak hours when the sun’s rays are the strongest.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 3 | moderate | 30 min |
| 09:00 | 6 | high | 25 min |
| 10:00 | 8 | very high | 15 min |
| 11:00 | 11 | extreme | 10 min |
| 12:00 | 12 | extreme | 10 min |
| 13:00 | 11 | extreme | 10 min |
| 14:00 | 10 | very high | 15 min |
| 15:00 | 7 | high | 25 min |
| 16:00 | 4 | moderate | 30 min |
| 17:00 | 2 | low | 45 min |
| 18:00 | 1 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, UV exposure varies significantly, with notable peaks in the warmer months. January and December have a moderate UV Index of 4, allowing for 30-minute burn times, while February poses a high risk with an index of 6 and a burn time of 25 minutes. The risk escalates dramatically from March to August, reaching an extreme level of 12 during the summer months, where the burn time drops to just 10 minutes. April and May also highlight this extreme risk, prompting heightened caution. As temperatures cool down in September and October, the UV levels remain comparatively high, ranging from 9 to 8, before tapering off again in November. Given this seasonal fluctuation, it is strongly advised that visitors and residents take precautions—such as wearing sunscreen, protective clothing, and sunglasses—especially from March to August, when UV exposure is at its most hazardous.
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 |
| Tonto Basin | 4 | 6 | 9 | 11 | 12 | 12 | 12 | 11 | 10 | 8 | 6 | 4 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |