Last updated: July 2, 2025
Understanding the UV Index is crucial for residents and visitors in San Antonio, given the city's warm, humid Cfa climate which often leads to elevated UV exposure. As the sun's rays can be particularly harsh, especially during midday hours, awareness of UV levels is essential for preventing sunburns and safeguarding skin health. With a peak UV Index reaching as high as 12 in the afternoon, it's vital to take protective measures to enjoy the sun safely. Whether you're lounging outdoors or engaging in recreational activities, knowing the UV Index can help you make informed decisions to protect yourself and your loved ones from potential harm.
The UV Index today presents a striking rise in intensity throughout the morning, beginning at a low of 1 at 07:00. As the day progresses, especially from 10:00 onwards, the index takes a dramatic leap, peaking at a scorching 12 between 13:00 and 14:00. This intense exposure underscores a need for protective measures during those hours. As the sun begins to set, the index gradually declines, returning to 1 by 19:00, indicating a safer end to the day. Overall, today’s UV trend highlights the importance of sun protection during peak hours, particularly between 11:00 and 15:00.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 2 | low | 45 min |
| 10:00 | 5 | moderate | 30 min |
| 11:00 | 7 | high | 25 min |
| 12:00 | 10 | very high | 15 min |
| 13:00 | 12 | extreme | 10 min |
| 14:00 | 12 | extreme | 10 min |
| 15:00 | 10 | very high | 15 min |
| 16:00 | 7 | high | 25 min |
| 17:00 | 5 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, UV levels exhibit significant seasonal changes. January sees a moderate UV Index of 5, while February and March jump to 8 and 9, respectively, indicating very high exposure risks with short burn times of just 15 minutes. The peak months for UV exposure are from April to August, where the Index reaches an extreme level of 11 to 12, necessitating caution with a burn time of only 10 minutes. As the year progresses, UV levels decrease, but October remains notably high at 9, followed by November with a high category of 7. For visitors and residents alike, it is crucial to take protective measures during the high-risk months of April through September and remain vigilant, using sunscreen, wearing protective clothing, and seeking shade to minimize the risk of skin damage.
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 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |
| San Antonio | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 12 | 11 | 9 | 7 | 5 |