Last updated: July 2, 2025
Understanding the UV Index is crucial for residents and visitors of San Juan Sayultepec, Mexico, where the Cwb climate contributes to varying sun exposure throughout the day. As UV levels can rapidly increase, particularly between 11:00 AM and 2:00 PM—reaching a peak of 15—being aware of these changes is vital for sunburn prevention and maintaining skin health. This awareness can help you enjoy the sun safely while minimizing potential damage during peak hours, ensuring that your time in this beautiful region remains both enjoyable and healthy.
The UV Index data paints a vibrant picture of sunlight intensity throughout the day. Beginning with a mild UVI of 1 at 7:00 AM, the day starts gently, gradually climbing to 3 by 9:00 AM. However, as the sun reaches its zenith, the UVI skyrockets, peaking at an intense 15 between 1:00 PM and 2:00 PM. During these hours, it's crucial to take protective measures against harmful UV rays. As the sun begins to set, the index dips, dropping to 5 by 5:00 PM and returning to a safer 1 by 7:00 PM. This fluctuation highlights the importance of staying sun-smart during peak hours, especially between 11:00 AM and 2:00 PM when the UVI is at its highest.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 3 | moderate | 30 min |
| 10:00 | 6 | high | 25 min |
| 11:00 | 10 | very high | 15 min |
| 12:00 | 13 | extreme | 10 min |
| 13:00 | 15 | extreme | 10 min |
| 14:00 | 15 | extreme | 10 min |
| 15:00 | 13 | extreme | 10 min |
| 16:00 | 9 | very high | 15 min |
| 17:00 | 5 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
The UV Index exhibits a notable seasonal pattern, peaking during the warmer months from March to October, where values consistently remain in the extreme category (UV Index 14-15). The highest UV levels are recorded in April, May, June, and July, maintaining an extreme classification and a very short burn time of just 10 minutes. In contrast, January and December experience very high UV levels but with slightly longer burn times of 15 minutes. Based on this data, the high-risk months for UV exposure are clearly March through November, especially from April to August. Visitors and residents are advised to take precautionary measures during these months—such as wearing sunscreen, protective clothing, and seeking shade during peak hours—to minimize the risk of sunburn and long-term 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 |
| 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 |
| San Juan Sayultepec | 10 | 13 | 14 | 15 | 15 | 15 | 15 | 14 | 14 | 13 | 11 | 9 |