Last updated: June 2, 2025
In Stanford, United States, being aware of the UV Index is crucial for safeguarding your skin and overall health. Understanding the daily UV levels helps you effectively prevent sunburn and long-term skin damage, especially during peak hours when the sun’s rays are most intense. In this Cfa climate zone, residents can expect varied UV exposure, with indexes reaching as high as 11 around midday, indicating extreme risk. By staying informed about the UV Index, you can enjoy the beautiful Californian sunshine while protecting yourself from its harmful effects.
The UV Index throughout the day showcases an intriguing pattern of intensity. Starting low at 07:00 and 08:00, with a manageable score of 1, the sun's rays gradually intensify. By 09:00, the index climbs to 3, hinting at a warmer day ahead. The peak arrives at noon, hitting a striking 9, and just a little later, the UVI reaches its zenith at 13:00 and 14:00, both at an impressive 11. As the afternoon progresses, the UV exposure starts to wane, dipping to 9 at 15:00 and further decreasing to 5 by 17:00. The evening cools down significantly, with the index returning to the comfortable levels of 3 at 18:00 and finally resting at 1 by 19:00. Stay protected and enjoy the sun, especially during those peak hours!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 3 | moderate | 30 min |
| 10:00 | 5 | moderate | 30 min |
| 11:00 | 7 | high | 25 min |
| 12:00 | 9 | very high | 15 min |
| 13:00 | 11 | extreme | 10 min |
| 14:00 | 11 | extreme | 10 min |
| 15:00 | 9 | very high | 15 min |
| 16:00 | 7 | high | 25 min |
| 17:00 | 5 | moderate | 30 min |
| 18:00 | 3 | moderate | 30 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, the UV Index experiences significant fluctuations, indicating varying levels of sun exposure risk. The high-risk months for UV exposure are primarily from April to August, where indices peak at 11 in June and July, categorized as extreme with a burn time of only 10 minutes. It is crucial for both visitors and residents to take precautions during this period, such as wearing protective clothing and applying sunscreen frequently. As spring transitions into summer, the UV index rises sharply, reaching very high levels in May and August, and dropping to high in March and October. The months of January, November, and December see lower risks with a moderate index of 3 or 5, allowing for more extended safe sun exposure times of 30 minutes. Visitors and residents should monitor UV levels closely and adjust outdoor activities accordingly to safeguard their skin health.
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 |
| Stanford | 3 | 6 | 7 | 9 | 10 | 11 | 11 | 10 | 9 | 7 | 5 | 3 |
| 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 |