Last updated: July 2, 2025
Understanding the UV Index is crucial for residents of Johnson, United States, where sun exposure can vary significantly throughout the day. With a Dfb climate, this region experiences distinct seasons that can influence UV levels, peaking at an intensity of 9 around midday. Awareness of UV levels is essential for preventing sunburn and protecting skin health, especially during the warmer months. By keeping an eye on the UV Index, residents can take proactive steps to enjoy the outdoors safely while minimizing the risk of harmful effects from sun exposure.
As the sun rises, the UV Index begins its ascent, reaching a gentle 1 at 07:00. By 08:00, it doubles to 2, slowly warming up for the day ahead. Things heat up significantly by 09:00, hitting 4, and by 10:00, it climbs to a peak of 6. The zenith arrives at 12:00, where the index stands tall at 8, and by 13:00, it reaches a sizzling 9—the highest point of the day. As the afternoon wears on, the UV intensity begins to wane, dropping to 8 at 14:00 and then to 6 at 15:00. By 16:00, it cools further to 5, retreating to 3 by 17:00. The evening brings relief as the UV Index transitions back down to 2 at 18:00 and finally returns to a mild 1 by 19:00. This hourly journey highlights the importance of sun safety, especially during those midday hours when the UV rays are at their fiercest.
| 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 | 6 | high | 25 min |
| 11:00 | 7 | high | 25 min |
| 12:00 | 8 | very high | 15 min |
| 13:00 | 9 | very high | 15 min |
| 14:00 | 8 | very high | 15 min |
| 15:00 | 6 | high | 25 min |
| 16:00 | 5 | moderate | 30 min |
| 17:00 | 3 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
The UV Index exhibits significant seasonal changes, with the highest levels occurring from April to August. During this peak period, particularly in May and June, the UV Index reaches 10 and 9, categorized as very high, indicating a burn time of only 15 minutes. Visitors and residents should pay special attention to April through August as these months represent the highest risk for UV exposure. In contrast, January, December, and November show much lower UV levels, categorized as low or moderate, allowing for longer exposure times of 30 to 45 minutes without significant risk. It is advisable for individuals to seek shade, wear protective clothing, and apply sunscreen, particularly during the high-risk months from April to August, to minimize the chance of skin damage.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Johnson | 2 | 4 | 5 | 7 | 9 | 10 | 9 | 9 | 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 |