Last updated: June 2, 2025
Understanding the UV Index is crucial for residents and visitors of San Juan, Puerto Rico, where the tropical climate leads to increased sun exposure year-round. Being aware of UV levels helps in preventing sunburn, protecting skin health, and reducing the risk of long-term damage. With midday UV Index values soaring as high as 13, San Juan poses significant challenges for those unaccustomed to its intense sun, particularly during peak hours. By monitoring the UV Index, you can enjoy the beautiful beaches and vibrant outdoors while taking essential precautions to safeguard your skin.
The UV Index begins at a mild level of 1 at 07:00, but as the sun climbs higher, it swiftly escalates. By 10:00, it peaks at a critical 9, reaching a maximum of 13 at 12:00, indicating that protective measures are essential. After noon, the index gradually declines, tapering to 7 by 15:00, before dipping to a 2 by 17:00, and finally settling at 0 by 19:00 as the sun sets. This data highlights the importance of sun safety during the hours when UV exposure is at its highest, particularly around midday.
Time | UVI | Category | Time to Burn |
---|---|---|---|
07:00 | 1 | low | 45 min |
08:00 | 3 | moderate | 30 min |
09:00 | 5 | moderate | 30 min |
10:00 | 9 | very high | 15 min |
11:00 | 11 | extreme | 10 min |
12:00 | 13 | extreme | 10 min |
13:00 | 12 | extreme | 10 min |
14:00 | 10 | very high | 15 min |
15:00 | 7 | high | 25 min |
16:00 | 4 | moderate | 30 min |
17:00 | 2 | low | 45 min |
18:00 | 1 | low | 45 min |
19:00 | 0 | low | 45 min |
The UV Index shows significant seasonal variation, peaking during the months of March to October, when levels reach between 12 and 14, categorizing them as extreme with a burn time of just 10 minutes. The highest risk months are April, May, and August, where the UV Index reaches 13 to 14. In contrast, January, February, and November still present very high exposure risks with less urgency, allowing for burn times of 15 minutes. Visitors and residents are strongly advised to take protective measures during the high UV months by wearing sunscreen, protective clothing, and sunglasses, and to limit sun exposure, especially during midday hours when the sun's rays are strongest.
UV Risk Categories
Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
---|---|---|---|---|---|---|---|---|---|---|---|---|
San Juan | 9 | 11 | 13 | 13 | 14 | 13 | 12 | 13 | 13 | 12 | 9 | 8 |
Caguas UVI | 9 | 11 | 13 | 13 | 14 | 13 | 12 | 13 | 13 | 12 | 9 | 8 |
Carolina UVI | 9 | 11 | 13 | 13 | 14 | 13 | 12 | 13 | 13 | 12 | 9 | 8 |
Bayamon UVI | 9 | 11 | 13 | 13 | 14 | 13 | 13 | 13 | 13 | 12 | 9 | 8 |
Ponce UVI | 9 | 11 | 13 | 14 | 14 | 13 | 13 | 13 | 14 | 12 | 10 | 9 |