Last updated: June 2, 2025
Staying informed about the UV Index in Stanford, United States, is crucial for safeguarding your skin health and preventing painful sunburns. Understanding UV levels helps residents make informed decisions about outdoor activities, especially during peak exposure times. With a Dfa climate, Stanford experiences significant sunlight throughout the year, making it essential to be aware of fluctuating UV risks. As the midday UV Index can reach a high of 11, even short periods under the sun can lead to harmful effects. Equip yourself with this knowledge to enjoy the beautiful Californian outdoors while protecting your skin!
The UV Index steadily climbs as the day progresses, starting from a mild 1 at 7:00 AM and reaching a peak of 11 by 1:00 PM. Sun-seekers and outdoor enthusiasts should be mindful, as the index hits a high of 10 at 12:00 PM, signaling significant UV exposure. After this peak, the index gradually decreases, dropping to 8 by 3:00 PM, and continuing to decline to 1 by 7:00 PM. For safe sun enjoyment, it’s best to take precautions during those high UV hours, particularly between 11:00 AM and 2:00 PM. Remember to sport your hats and sunscreen!
| 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 | 6 | high | 25 min |
| 11:00 | 9 | very high | 15 min |
| 12:00 | 10 | very high | 15 min |
| 13:00 | 11 | extreme | 10 min |
| 14:00 | 10 | very high | 15 min |
| 15:00 | 8 | very high | 15 min |
| 16:00 | 6 | high | 25 min |
| 17:00 | 3 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
As the seasons change, so do the UV Index levels, significantly affecting sun exposure and burn times throughout the year. From January to February, UV levels remain moderate (3-5), allowing for a 30-minute burn time. However, starting in March, the UV Index rises to 7, indicating high exposure risk with burn times of 25 minutes. The peak risk occurs from April to June, where the UV Index hits 9-11, classifying these months as very high to extreme (with burn times reduced to 10-15 minutes). July and August maintain high levels of sun intensity, but begin to taper off in September (UV Index 8). By October, the UV Index decreases to 6, marking a return to high exposure risk, while November and December offer moderate to low levels (4 and 2 respectively), allowing for longer burn times. Visitors and residents are advised to take extra precautions during high-risk months (March to September) by wearing protective clothing and applying sunscreen regularly, particularly when UV levels are at their peak.
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 | 5 | 7 | 9 | 10 | 11 | 10 | 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 |