Last updated: June 2, 2025
Understanding the UV Index in San Marcos is crucial for protecting your skin from harmful ultraviolet radiation. As a resident or visitor in this sunny region, being aware of daily UV levels helps in preventing painful sunburns and long-term skin damage. San Marcos, situated in a Csa climate zone, generally experiences high UV exposure, especially during midday hours when the index can soar to 12. By learning about the UV Index, you empower yourself to make informed decisions about sun safety, ensuring you enjoy the beautiful weather while keeping your skin healthy and protected.
The UV Index reveals a dynamic dance of sun intensity throughout the day, peaking dramatically at the highest levels between 12:00 PM and 1:00 PM. Starting the morning gentle with a UV Index of 1 at 7:00 AM, it quickly escalates as the sun rises, hitting 2 by 8:00 AM and surging to 11 by noon. The maximal exposure occurs at 1:00 PM with a striking 12, indicating a period of high sun intensity that calls for caution. As the afternoon progresses, the index gradually declines, reaching a comfortable 3 by 5:00 PM and settling back to 1 by 7:00 PM. This rhythmic pattern serves as a reminder to stay sun-safe during peak hours!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 2 | low | 45 min |
| 09:00 | 4 | moderate | 30 min |
| 10:00 | 7 | high | 25 min |
| 11:00 | 10 | very high | 15 min |
| 12:00 | 11 | extreme | 10 min |
| 13:00 | 12 | extreme | 10 min |
| 14:00 | 11 | extreme | 10 min |
| 15:00 | 8 | very high | 15 min |
| 16:00 | 6 | high | 25 min |
| 17:00 | 3 | moderate | 30 min |
| 18:00 | 1 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, UV exposure varies significantly, with the highest UV Index levels observed from March to August. The months of May and June peak at an extreme UV Index of 11 and 12, where the burn time drops to just 10 minutes, posing a significant risk for sunburn. March and April also present substantial risks, classified as very high with an Index of 9 and 10, and a burn time of 15 minutes. As summer wanes into autumn, the UV Index begins to decrease, but September and October still remain at high levels with burn times of 15 to 25 minutes. Therefore, visitors and residents are strongly advised to prioritize sun safety, especially during the high-risk months of March through August by wearing protective clothing, using sunscreen, and seeking shade during peak sun hours.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chicago UVI | 3 | 4 | 6 | 8 | 9 | 10 | 10 | 9 | 8 | 6 | 4 | 2 |
| Brooklyn UVI | 3 | 5 | 6 | 8 | 10 | 10 | 9 | 9 | 8 | 6 | 4 | 2 |
| New York City UVI | 3 | 5 | 6 | 8 | 10 | 10 | 9 | 9 | 8 | 6 | 4 | 2 |
| Los Angeles UVI | 4 | 6 | 8 | 9 | 10 | 11 | 11 | 10 | 10 | 7 | 5 | 4 |
| San Marcos | 4 | 6 | 9 | 10 | 11 | 12 | 11 | 10 | 10 | 7 | 5 | 4 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |