Last updated: June 2, 2025
Understanding the UV Index is crucial for residents of Johnson, United States, where the semi-arid climate (BSk) can often lead to higher UV exposure, especially during the summer months. Being aware of UV levels is essential not only for preventing painful sunburns but also for maintaining long-term skin health, as excessive UV radiation can increase the risk of skin cancer. During peak hours, particularly from 10 AM to 2 PM, the UV Index can soar, reaching levels of 12—indicating a very high risk of harm from unprotected sun exposure. By staying informed about the UV Index, you can take proactive steps to protect yourself and your loved ones while enjoying the beautiful outdoors.
The UV Index throughout the day shows a dynamic fluctuation in sun intensity. Early morning, at 07:00 and 08:00, the index remains low at 1, indicating minimal sun exposure risk. As the sun rises, the index climbs to 3 by 09:00, then reaches a moderate level of 5 by 10:00. The real intensity kicks in at 11:00 with a peak of 8, and by 12:00, the UV Index surges to 10, signaling high exposure risk. The afternoon carries the highest readings, with a maximum of 12 at both 13:00 and 14:00, creating a need for sun protection. Following this peak, the index gradually declines, dropping to 11 at 15:00, and then easing to 8 at 16:00. As the day winds down, the index falls to 6 by 17:00 and continues to decrease through the evening, resting at a gentle 2 by 19:00. Overall, today’s UV Index reveals a typical midsummer day where one must be cautious during the peak hours of sunlight.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 3 | moderate | 30 min |
| 10:00 | 5 | moderate | 30 min |
| 11:00 | 8 | very high | 15 min |
| 12:00 | 10 | very high | 15 min |
| 13:00 | 12 | extreme | 10 min |
| 14:00 | 12 | extreme | 10 min |
| 15:00 | 11 | extreme | 10 min |
| 16:00 | 8 | very high | 15 min |
| 17:00 | 6 | high | 25 min |
| 18:00 | 3 | moderate | 30 min |
| 19:00 | 2 | low | 45 min |
The UV Index experiences notable seasonal fluctuations, significantly impacting sun exposure risk throughout the year. From January to February, UV levels remain moderate, making burn times approximately 30 minutes. However, as spring arrives in March and peaks in April, the UV Index surges to very high levels of 8 and 10, respectively, reducing burn times to just 15 minutes. The summer months of May through August present the highest risk, with extreme UV Index readings of 11 to 12 and burn times dropping to 10 minutes. In September, the risk diminishes slightly but remains very high, while by October, it further decreases to a high index of 7, allowing for a burn time of 25 minutes. As winter approaches, November and December return to moderate UV levels. Visitors and residents are advised to take protective measures during the high-risk months of March to September, including using sunscreen, wearing protective clothing, and seeking shade whenever possible.
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 |
| Johnson | 4 | 5 | 8 | 10 | 11 | 12 | 12 | 11 | 10 | 7 | 5 | 3 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |