UV Index in San Marcos, United States

Last updated: May 3, 2025

Understanding the UV Index in San Marcos, United States is crucial for safeguarding your skin health, especially under the region's warm climate. With peak UV levels reaching 12 during midday, awareness of these levels can help prevent sunburn and reduce long-term skin damage. Given San Marcos’ typical climate—characterized by hot summers and sunny days—being informed about UV exposure risks is essential for everyone, whether you're enjoying outdoor activities or simply soaking up the sun. Stay vigilant and make sun safety a priority!

Hourly UV Index in San Marcos

The day begins gently with a UV Index of 1 at both 07:00 and 08:00, indicating minimal sun exposure. However, as the clock strikes 09:00, the index rises to 3, signifying a gradual increase in UV intensity. By 10:00, it reaches 5, and the sun takes center stage at 11:00 with a striking 8. The peak arrives at 12:00, soaring to an impressive 10, and continues to climb, hitting its pinnacle with a dazzling 12 at 13:00. As the afternoon unfolds, values begin a slow descent: 11 at 14:00, 10 at 15:00, and then dropping to 7 by 16:00. The evening brings relief, with the index tapering down to 4 at 17:00, 2 at 18:00, and finally returning to a safe 1 by 19:00. Remember to stay protected during those peak hours!

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.
TimeUVICategoryTime to Burn
07:001low45 min
08:001low45 min
09:003moderate30 min
10:005moderate30 min
11:008very high15 min
12:0010very high15 min
13:0012extreme10 min
14:0011extreme10 min
15:0010very high15 min
16:007high25 min
17:004moderate30 min
18:002low45 min
19:001low45 min

Monthly UV Index Trends in San Marcos

The UV Index exhibits significant seasonal variation, with the highest levels typically occurring from April to September. During these months, the UV Index reaches extremes of 11 to 12, categorizing them as extreme exposure. February through October are considered high-risk months, especially April to August, where the burn time is as short as 10 minutes. It is vital for residents and visitors to take precautions, such as wearing sunscreen, protective clothing, and seeking shade during peak sunlight hours to minimize the risk of skin damage. As the UV Index decreases in the fall and winter months, November and December present lower risk, with more moderate values of 6 and 5, allowing for longer exposure times before burning occurs. Adjusting outdoor activities according to the UV index is essential for ensuring safety and health throughout the year.

Monthly Maximum UV Index for San Marcos, United States

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in San Marcos. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.
JanFebMarAprMayJunJulAugSepOctNovDec589111212121210965
Data source: Statistical UV Index data for San Marcos, 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 Marcos UV Index with Other United States Cities

The table above highlights how UV exposure in San Marcos compares to other major locations across United States. This comparison helps travelers and residents better understand regional sun intensity and plan outdoor activities with sun safety in mind.
San Marcos's solar exposure compared to other cities in United States. Generated using Copernicus Atmosphere Monitoring Service information.
 JanFebMarAprMayJunJulAugSepOctNovDec
Chicago UVI34689101098642
Brooklyn UVI35681010998642
New York City UVI35681010998642
Los Angeles UVI46891011111010754
San Marcos589111112121211965
Houston UVI589111112121110975