Last updated: May 3, 2025
Understanding the UV Index is crucial for residents and visitors of San Francisco (Oyozontle), Mexico, as it directly impacts skin health and sunburn prevention. The UV Index provides vital information about the intensity of ultraviolet radiation, helping you make informed decisions about sun exposure. With a climate characterized by a mix of tropical and arid conditions, San Francisco experiences noticeable variations in UV levels throughout the day. For example, during peak hours—between 11:00 AM and 2:00 PM—the UV Index can soar up to 13, indicating extreme risk of harm from unprotected sun exposure. Staying aware of these levels is essential for enjoying the sun safely while protecting your skin.
As the sun rises, the UV Index begins modestly at 1 between 07:00 and 08:00, signaling a gentle start to the day. However, by 09:00, it's on the rise to 3, hinting at the increasing intensity of UV radiation. The midday hours see a dramatic surge, peaking at a scorching 13 by 13:00. This period between 11:00 and 14:00 is particularly critical, with values soaring to 9 and 12, urging caution for outdoor activities. As the afternoon rolls in, the index gradually retreats, dropping to 11 at 15:00 and then declining further to 4 by 17:00, indicating a safe return to outdoor pursuits as evening approaches. The UV risk diminishes significantly by 18:00, resting at 2, before settling back to 1 as dusk falls. Stay sun smart and protect your skin during those peak hours!
| 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 | 9 | very high | 15 min |
| 12:00 | 12 | extreme | 10 min |
| 13:00 | 13 | extreme | 10 min |
| 14:00 | 13 | extreme | 10 min |
| 15:00 | 11 | extreme | 10 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, the UV Index experiences significant fluctuations, peaking during the summer months. From January to March, the UV Index rises progressively from 9 to 12, marking the start of higher sun exposure risks with burn times decreasing to 10 minutes by late winter. The months of April to September present the highest danger, with the UV Index reaching its max of 14 in July. The exposure category remains at extreme throughout this period, indicating a burn time of just 10 minutes. As we move into fall, the UV Index drops slightly but stays within the extreme category until October, before retreating to very high levels in November and December. Residents and visitors should exercise caution and take protective measures during high-risk months, particularly from March to October, when the potential for skin damage is considerably elevated. Always apply sunscreen, wear protective clothing, and seek shade during peak hours to minimize risks.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| San Francisco (Oyozontle) | 9 | 11 | 12 | 13 | 13 | 13 | 14 | 12 | 13 | 11 | 9 | 8 |
| 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 |