Last updated: May 3, 2025
Understanding the UV Index is crucial for residents and visitors in California, where the sun’s rays can be intense, especially during the peak hours of the day. As a state known for its picturesque beaches and endless sunshine, Californians face significant risks of sunburn and long-term skin health issues if they don’t stay informed about UV levels. With readings often reaching a maximum of 10 around midday, it's essential to understand how these levels correlate with potential harmful effects. By being aware of the UV Index, you can take proactive measures to protect your skin and enjoy the outdoors safely in California's vibrant, sun-soaked climate.
The hourly UV Index data reveals a dynamic shift in sun intensity throughout the day, starting from a gentle 1 at 07:00, ideal for morning strolls. As the sun rises higher, the index escalates, peaking at a potent 10 between 12:00 and 13:00. This mid-day surge emphasizes the need for sunscreen and protective gear, as the risk of harm from UV rays increases significantly. By 15:00, the index begins to decline, settling at 7 before tapering off further to a mere 1 by 19:00, signaling a safe reprieve for evening outdoor activities. Stay aware and protect your skin during those 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 | 6 | high | 25 min |
| 11:00 | 8 | very high | 15 min |
| 12:00 | 10 | very high | 15 min |
| 13:00 | 10 | very high | 15 min |
| 14:00 | 9 | very high | 15 min |
| 15:00 | 7 | high | 25 min |
| 16:00 | 5 | moderate | 30 min |
| 17:00 | 3 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, UV exposure varies significantly, with the high-risk months spanning from April to September. During this period, the UV Index reaches very high levels, peaking at 10 in May, June, July, and August, where the burn time is as short as 15 minutes. In contrast, January, February, November, and December present moderate risk with an Index of 3 to 5, allowing up to 30 minutes of safe sun exposure. Residents and visitors should take precautions during the spring and summer months, including wearing protective clothing, using sunscreen with high SPF, and seeking shade during peak hours to minimize the risk of sunburn and long-term skin damage. Remember, even on cloudy days, UV rays can still penetrate, so remain vigilant year-round.
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 |
| California | 3 | 5 | 7 | 9 | 10 | 10 | 10 | 10 | 8 | 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 |