UV Index in San Juan, Puerto Rico

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.

Hourly UV Index in San Juan

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.

Average solar exposure data for the current time of the year. Actual values may vary and depend on many factors, such as cloud cover, vegetation cover, surface type, etc.
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

Monthly UV Index Trends in San Juan

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.

Monthly Maximum UV Index for San Juan, Puerto Rico

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in San Juan. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.

Data source: Statistical UV Index data for San Juan, based on information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

Compare San Juan UV Index with Other Puerto Rico Cities

The table above highlights how UV exposure in San Juan compares to other major locations across Puerto Rico. This comparison helps travelers and residents better understand regional sun intensity and plan outdoor activities with sun safety in mind.

San Juan's solar exposure compared to other cities in Puerto Rico. Generated using Copernicus Atmosphere Monitoring Service information.
	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