Last updated: July 2, 2025
In San Guillermo la Reforma, Mexico, understanding the UV Index is crucial for maintaining skin health and preventing sunburns. With a climate categorized as Cwb, the region experiences significant UV exposure, especially during peak hours, where the UV Index can soar to 15 by midday. Being aware of these levels empowers residents and visitors alike to take necessary precautions, ensuring their time outdoors is both enjoyable and safe. By staying informed about UV risks, you can protect your skin and embrace the beautiful sunny days that San Guillermo la Reforma has to offer!
As the sun rises, the UV Index starts off modestly, peaking at 1 by 8:00 AM. However, as the day progresses, it experiences a dramatic surge. Expect a notable climb by 10:00 AM, hitting 5, and then reaching its zenith at 1:00 PM with an impressive 15. The intensity remains high throughout the afternoon, only slightly easing towards the evening. By 6:00 PM, the index drops to 3, and settles back to 1 by 7:00 PM. It's a reminder to stay sun-safe during peak hours, especially from 11:00 AM to 2:00 PM, when the UV radiation is strongest!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 2 | low | 45 min |
| 10:00 | 5 | moderate | 30 min |
| 11:00 | 9 | 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 | 10 | very high | 15 min |
| 17:00 | 6 | high | 25 min |
| 18:00 | 3 | moderate | 30 min |
| 19:00 | 1 | low | 45 min |
During the year, seasonal UV changes show significant fluctuations, with highest UV levels occurring from February to October. This period includes several high-risk months for sun exposure, particularly from March to October, where the UV Index reaches extreme levels (14-15), with a burn time of just 10 minutes. Conversely, January, November, and December experience very high UV Index ratings (9-10), with longer burn times of 15 minutes. Visitors and residents are strongly advised to take extra precautions during these high-risk months, including wearing protective clothing, applying broad-spectrum sunscreen with an SPF of 30 or higher, and seeking shade during peak hours to minimize the risk of UV-related harm.
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 |
| San Guillermo la Reforma | 9 | 12 | 14 | 15 | 15 | 15 | 15 | 14 | 14 | 13 | 10 | 8 |
| Puebla UVI | 10 | 12 | 14 | 15 | 15 | 15 | 15 | 14 | 14 | 13 | 10 | 9 |