Last updated: May 3, 2025
Understanding the UV Index is crucial for residents of Lake Forest, United States, where the sunlight can be intense, especially during peak hours. Knowing the UV levels not only helps in preventing painful sunburn but also plays a vital role in long-term skin health. With a Csa climate characterized by warm summers, the UV Index can reach high levels, peaking at an alarming 11 around noon. Being aware of these fluctuations empowers you to take necessary precautions, ensuring you enjoy the beautiful sunny days without compromising your skin's well-being.
At 07:00, the UV Index begins its climb with a modest level of 1. By 08:00, it doubles to 2, signaling the start of a gradual increase in solar intensity. As the sun rises higher, the index swiftly escalates to 4 by 09:00 and reaches a brisk 7 at 10:00. The peak occurs at 12:00, hitting a notable 10, and it continues to soar, reaching its maximum of 11 by 13:00. After this midday peak, the UV Index begins to decline, dropping to 9 at 14:00 and gradually decreasing to 7 by 15:00. As the afternoon progresses, it further retreats to 5 at 16:00 and falls to 3 by 17:00, finally settling back to 1 at 18:00 and 19:00. This prompts a reminder to take essential sun protection during the day, especially when the index is at its highest!
| 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 | 7 | high | 25 min |
| 11:00 | 9 | very high | 15 min |
| 12:00 | 10 | very high | 15 min |
| 13:00 | 11 | extreme | 10 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 | 1 | low | 45 min |
| 19:00 | 1 | low | 45 min |
As the seasons change, so do the UV index levels, significantly impacting sun safety practices. January sees a moderate UV index of 4, allowing for 30 minutes of potential sun exposure. However, by February, the UV index rises to 6 (high), reducing safe burn time to 25 minutes. The risk escalates from March through July, with values peaking at 11 (extreme) during May and June, necessitating caution with just 10 minutes of safe exposure. August and September remain high at 10 (very high), with 15 minutes of burn time, before a gradual decline begins in October with a 7 (high) index. Throughout November and December, the index returns to a moderate 5 and 4, allowing for safe exposure up to 30 minutes. For both visitors and residents, it is crucial to be particularly vigilant during the high-risk months of March to September, taking proactive measures such as wearing sunscreen, protective clothing, and seeking shade during peak sun hours to safeguard against harmful UV radiation.
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 |
| Lake Forest | 4 | 6 | 8 | 10 | 11 | 11 | 11 | 10 | 10 | 7 | 5 | 4 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |