Last updated: July 2, 2025
Understanding the UV Index is crucial for everyone in Perth, United States, as it provides essential information about ultraviolet radiation levels that can pose significant risks to skin health. With the potential for sunburn and long-term skin damage, staying informed about UV levels helps residents and visitors take necessary precautions during peak exposure times. Perth's Dfb climate contributes to high UV levels, especially around midday when readings can soar to 9, indicating a need for proactive sun safety measures. By keeping an eye on the UV Index, you can enjoy the sunny outdoors while protecting your skin.
The UV Index throughout the day tells a compelling story of sun exposure. Starting at a gentle 1 at 7:00 AM, it gradually rises, reaching 2 by 8:00 AM. As the clock ticks towards mid-morning, the intensity ramps up, peaking at 9 between 12:00 PM and 2:00 PM—the perfect time for a shaded respite or sunscreen application. By 11:00 AM, the index hits 7, signaling more significant sun intensity. As the afternoon wanes, it starts to dip, falling to 3 by 5:00 PM, and eventually returning to 1 by 7:00 PM. This data emphasizes the importance of sun protection, particularly during those peak hours, to ensure a safe and enjoyable day outdoors!
| 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 | 9 | very high | 15 min |
| 13:00 | 9 | very high | 15 min |
| 14:00 | 9 | very high | 15 min |
| 15:00 | 7 | 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 |
As the seasons change, the UV Index reveals significant fluctuations in sun exposure risk. Winter months (January and February) have moderate UV levels with an index of 3 to 4, leading to a burn time of approximately 30 minutes. Transitioning into spring, the UV Index rises sharply: March reaches a high of 6, and by April it soars to 8, signaling the start of very high risk months with a burn time reduced to 15 minutes. The summer months (May through August) maintain this high threat level, peaking at 10 in June, necessitating extra precautions for outdoor activities. As September and October approach, the UV Index decreases to 7 and 6, respectively, still indicating a high risk for 25 minutes of safe sun exposure. November and December see a return to moderate and low levels for UV exposure, with longer burn times of 30 to 45 minutes. Residents and visitors are advised to take protective measures, especially from April to August, including wearing sunscreen, protective clothing, and limiting time in direct sunlight during peak hours.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Perth | 3 | 4 | 6 | 8 | 9 | 10 | 9 | 9 | 7 | 6 | 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 |