Last updated: July 2, 2025
Understanding the UV Index is crucial for residents of San Ysidro, where the warm climate can lead to increased exposure to harmful ultraviolet radiation. Being aware of UV levels not only helps in preventing sunburn but also plays a vital role in maintaining long-term skin health. With peak UV Index readings often reaching 12 during midday, residents must take proactive measures to protect themselves, especially given the area's typical BWk climate that contributes to higher UV exposure risks. By staying informed and vigilant, you can enjoy the sunny days while safeguarding your skin.
Today's UV Index showcases a notable rise in intensity, peaking at 12 between 12:00 PM and 2:00 PM, a level that emphasizes the need for sun protection. Early risers will find a gentle start, with values of just 1 at 7:00 AM and gradually increasing to 9 by 11:00 AM. As the sun reaches its zenith, the relentless rays command attention, making 11:00 AM to 3:00 PM the prime time for caution. The index begins to taper off in the afternoon, dropping to 7 by 4:00 PM and further down to 1 by 7:00 PM, signaling a safe window for outdoor activities as evening approaches. Stay safe and enjoy the sun!
| 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 | 9 | very high | 15 min |
| 12:00 | 12 | extreme | 10 min |
| 13:00 | 12 | extreme | 10 min |
| 14:00 | 12 | extreme | 10 min |
| 15:00 | 10 | very high | 15 min |
| 16:00 | 7 | high | 25 min |
| 17:00 | 4 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, UV radiation levels fluctuate significantly, with the highest risk occurring between March and September. During this period, the UV Index reaches extreme levels, peaking at 13 in June, where the recommended burn time is just 10 minutes. April, May, July, August, and September also maintain extreme ratings, advising caution and proactive sun protection strategies. February and October present high to very high UV conditions, with slightly longer burn times of 25 and 15 minutes, respectively. January and December see a reduction to moderate UV levels, allowing for a more relaxed approach to sun exposure. Visitors and residents should stay vigilant, applying sunscreen, wearing protective clothing, and seeking shade during peak sun hours, particularly from March through September.
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 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |
| San Ysidro | 5 | 7 | 10 | 12 | 12 | 13 | 12 | 12 | 11 | 8 | 6 | 5 |