Last updated: July 2, 2025
Understanding the UV Index is crucial for residents and visitors in San Juan, Argentina, given the region's arid BWk climate that often leads to elevated sun exposure. Awareness of UV levels can significantly impact your skin health, helping you prevent sunburn and reduce the risk of long-term damage. With midday UV Index values peaking at 5, it’s important to take necessary precautions, especially during the intense hours between 11 AM and 3 PM when the sun's rays are most potent. Stay informed and protected to enjoy the sunny days that San Juan has to offer.
The UV Index throughout the day exhibits a dynamic pattern, starting from 0 at 7:00 AM and 8:00 AM, indicating minimal sun exposure risk. As the sun rises higher, the index gradually increases, reaching 1 by 9:00 AM and 10:00 AM. The sun's intensity peaks around 1:00 PM and 2:00 PM, climbing to a height of 5, signaling a moderate hazard to unprotected skin. In the afternoon, the UV Index begins to decline, dropping to 4 at 3:00 PM and then tapering off to 3 by 4:00 PM. As evening approaches, the level decreases further, arriving back at 1 by 5:00 PM and 6:00 PM, before finally settling at 0 at 7:00 PM. Be sure to protect your skin during the peak hours between 11:00 AM and 2:00 PM!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 0 | low | 45 min |
| 08:00 | 0 | low | 45 min |
| 09:00 | 1 | low | 45 min |
| 10:00 | 1 | low | 45 min |
| 11:00 | 3 | moderate | 30 min |
| 12:00 | 4 | moderate | 30 min |
| 13:00 | 5 | moderate | 30 min |
| 14:00 | 5 | moderate | 30 min |
| 15:00 | 4 | moderate | 30 min |
| 16:00 | 3 | moderate | 30 min |
| 17:00 | 1 | low | 45 min |
| 18:00 | 1 | low | 45 min |
| 19:00 | 0 | low | 45 min |
Throughout the year, UV exposure varies significantly, with the highest risk occurring in January, February, and March, all showing an extreme UV Index of 15 to 12, and a burn time of just 10 minutes. As we transition into the warmer months, April and September display a very high UV Index of 9, necessitating caution with a burn time of 15 minutes. The summer months of June and July offer a moderate level of UV exposure, allowing for a slightly extended burn time of 30 minutes. Notably, August shifts back to a high category with a UV Index of 7. As winter returns in October through December, UV levels rise back to extreme, emphasizing the need for protection with a burn time of 10 minutes. Visitors and residents are strongly advised to remain vigilant during high-risk months—especially from January to March and October to November—by wearing sunscreen, protective clothing, and seeking shade when the UV index is elevated.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Buenos Aires UVI | 14 | 13 | 11 | 7 | 5 | 4 | 4 | 6 | 8 | 10 | 13 | 14 |
| Rosario UVI | 14 | 13 | 11 | 8 | 5 | 4 | 4 | 6 | 8 | 11 | 13 | 14 |
| Mendoza UVI | 15 | 14 | 12 | 8 | 6 | 4 | 5 | 6 | 9 | 12 | 14 | 15 |
| Cordoba UVI | 15 | 13 | 12 | 9 | 6 | 4 | 5 | 7 | 9 | 12 | 14 | 15 |
| San Juan | 15 | 14 | 12 | 9 | 6 | 4 | 5 | 7 | 9 | 12 | 14 | 15 |
| San Miguel de Tucuman UVI | 15 | 14 | 13 | 10 | 7 | 5 | 6 | 7 | 10 | 13 | 15 | 15 |