Last updated: July 2, 2025
Understanding the UV Index is crucial for everyone living in or visiting Mexico and the United States, where the sun's rays can be particularly intense due to diverse climates. Being aware of UV levels can significantly aid in preventing sunburn and protecting your skin health, helping you enjoy the outdoors safely. In Mexico, where the climate features warm temperatures and clear skies, the risks of high UV exposure escalate throughout the day, peaking between 11 AM and 3 PM when the index can reach a formidable 9. With the right knowledge, you can take the necessary precautions to shield yourself from harmful UV radiation and make the most of your time in the sun.
The UV Index for the day showcases a notable rise in intensity as the sun climbs higher in the sky. Starting at a low of 1 at 7:00 AM, the index gradually increases to a moderate level of 3 by 9:00 AM. However, from 10:00 AM onward, things heat up significantly, peaking at a scorching 9 from noon to 2:00 PM. As the afternoon progresses, the UV Index gradually dips back to a friendly 3 by 5:00 PM, then descends further to 1 by the time evening sets in. This pattern underscores the importance of sun protection during peak hours, especially between 11:00 AM and 2:00 PM, when UV levels are at their highest.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 2 | low | 45 min |
| 09:00 | 3 | moderate | 30 min |
| 10:00 | 5 | moderate | 30 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 |
Throughout the year, UV levels fluctuate significantly, with notable increases during the spring and summer months. High-risk months for UV exposure occur from April to August, when the UV Index reaches its peak, particularly in June at 10, indicating a very high exposure category where burn time is only 15 minutes. In contrast, the winter months of January and December present lower risks, with a UV Index of 2 and burn times of 45 minutes. As UV levels change, residents and visitors are advised to take precautions during the warmer months, such as wearing protective clothing, applying sunscreen regularly, and seeking shade during peak sun hours. In the cooler months, while the risk is lower, it's still wise to remain vigilant, particularly during midday hours when UV rays can still pose a threat.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Mexico | 2 | 4 | 6 | 8 | 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 |