Last updated: July 2, 2025
In the West United States, awareness of the UV Index is crucial for safeguarding your skin health and preventing painful sunburns. Understanding UV levels helps residents and visitors alike take necessary precautions, especially during peak hours when the index reaches a maximum of 12 at noon. The region’s Cfa climate brings plenty of sunshine, making it essential to stay informed about typical UV exposure risks. By monitoring the UV Index, you can enjoy the outdoors safely while protecting your skin from harmful rays.
The UV Index throughout the day reveals a dynamic shift in sun intensity. In the early hours, from 7:00 to 9:00, the index remains low at 1 to 3, perfect for a leisurely morning stroll. However, as the sun climbs higher, the UV exposure peaks dramatically at 12:00 with an index of 10, reaching its highest point of 12 at 1:00 PM. This is the critical time for sun safety measures—sunscreen and protective clothing are essential! As the afternoon progresses, the intensity begins to wane, dropping to a 7 by 4:00 PM and further to a gentle 1 by 7:00 PM. Overall, it's a day marked by a sharp rise and gradual decline in UV levels, highlighting the importance of staying shielded during 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 | 8 | very high | 15 min |
| 12:00 | 10 | very high | 15 min |
| 13:00 | 12 | extreme | 10 min |
| 14:00 | 11 | 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, the UV Index experiences significant fluctuations, with the highest readings occurring from March to August. During April and May, the index peaks at 10 and 11, categorized as very high and extreme, respectively, resulting in a burn time as short as 10 minutes. The most high-risk months for UV exposure are typically from March to August, when precautions should be taken seriously. Visitors and residents are advised to use sunscreen, wear protective clothing, and seek shade, especially during peak hours from 11 a.m. to 4 p.m. In contrast, the months of January and December feature lower UV levels (UV Index of 4), indicating a moderate risk where exposure is less concerning, although protection is still recommended. Staying informed about the UV index can significantly reduce risks associated with sun exposure throughout the year.
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 |
| West | 4 | 7 | 8 | 10 | 11 | 12 | 12 | 11 | 10 | 8 | 6 | 4 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |