Last updated: July 2, 2025
Understanding the UV Index is crucial for everyone in Piedras Negras, Mexico, where the combination of a Cwa climate and intense sun exposure can lead to significant UV radiation risks. Knowledge of UV levels helps residents and visitors alike take proactive measures against sunburn and long-term skin health issues. With peak UV Index values soaring to 13 between noon and early afternoon, it’s essential to stay informed and protect your skin from the harmful effects of the sun. Whether enjoying outdoor activities or going about your daily routine, being UV-aware can make all the difference in preventing damage and ensuring a healthy lifestyle under the Mexican sun.
The UV index throughout the day reveals a dynamic pattern, starting from a low 0 at 7:00 AM and gradually climbing as the sun rises. By 10:00 AM, it reaches 4, signaling the start of potential sun sensitivity. As noon approaches, the intensity peaks dramatically at 12:00 PM with a UV index of 10, which is considered very high, urging outdoor enthusiasts to take protective measures. The afternoon hours continue to show significant UV levels, with a maximum of 13 at 1:00 PM and 2:00 PM, before slowly tapering off in the later afternoon and evening, dropping back to 1 by 7:00 PM. This data emphasizes the importance of sun safety, especially during the midday hours when UV exposure poses the greatest risk.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 0 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 2 | low | 45 min |
| 10:00 | 4 | moderate | 30 min |
| 11:00 | 7 | high | 25 min |
| 12:00 | 10 | very high | 15 min |
| 13:00 | 13 | extreme | 10 min |
| 14:00 | 13 | extreme | 10 min |
| 15:00 | 12 | extreme | 10 min |
| 16:00 | 9 | very high | 15 min |
| 17:00 | 6 | high | 25 min |
| 18:00 | 3 | moderate | 30 min |
| 19:00 | 1 | low | 45 min |
The seasonal UV changes indicate a significant increase in UV Index values from January to October, peaking at 14 during the months of March through June, categorized as extreme exposure with a burn time of only 10 minutes. Following this peak, UV levels gradually decrease but remain high in the late summer and early fall months, notably staying in the 13 range from July to September, before dropping to 12 in October. November and December see a return to very high levels, with indices of 9 and 8 respectively, allowing for slightly longer burn times of 15 minutes. As a result, it is crucial for both visitors and residents to take precautions during the high-risk months of February through October by wearing appropriate sun protection, seeking shade, and limiting sun exposure, especially during peak hours, to minimize the risk of skin damage.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Guadalajara UVI | 9 | 11 | 14 | 14 | 14 | 13 | 13 | 13 | 13 | 12 | 9 | 8 |
| Piedras Negras | 9 | 11 | 14 | 14 | 14 | 14 | 13 | 13 | 13 | 12 | 9 | 8 |
| Iztapalapa UVI | 10 | 12 | 14 | 15 | 14 | 14 | 14 | 14 | 14 | 12 | 10 | 8 |
| Ecatepec de Morelos UVI | 10 | 12 | 14 | 15 | 15 | 14 | 14 | 13 | 14 | 12 | 10 | 8 |
| Mexico City UVI | 10 | 12 | 14 | 15 | 15 | 14 | 14 | 13 | 14 | 12 | 10 | 8 |
| Puebla UVI | 10 | 12 | 14 | 15 | 15 | 15 | 15 | 14 | 14 | 13 | 10 | 9 |