Last updated: July 2, 2025
Understanding the UV Index is crucial for residents of McKinney, Texas, where sunny days are a hallmark of the Cfa climate. With UV levels peaking around midday, reaching as high as 11, awareness of these numbers can be the difference between a fun day outdoors and a painful sunburn. Protecting your skin is essential for long-term health, as elevated UV exposure is linked to skin damage and increased cancer risk. Stay informed about the UV Index to enjoy the beautiful McKinney weather while keeping your skin safe!
The UV Index for the day showcases a dramatic increase in intensity as the sun climbs higher in the sky. Starting at a mild 1 at 07:00, it remains low throughout the morning, only reaching 3 by 09:00. However, by 11:00, the index skyrockets to 8, peaking at an intense 11 from 13:00 to 14:00. As the afternoon wanes, the UV levels gradually decrease, dropping to 4 by 17:00 and tapering off to 1 once again by 19:00. It's clear that midday hours pose the greatest risk for sun exposure, making it crucial to take precautions during the peak hours from 11:00 to 14:00.
| 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 | 11 | extreme | 10 min |
| 14:00 | 11 | extreme | 10 min |
| 15:00 | 10 | very high | 15 min |
| 16:00 | 7 | high | 25 min |
| 17:00 | 4 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, ultraviolet (UV) exposure fluctuates significantly, necessitating awareness among residents and visitors. From January to April, the UV Index begins to rise, starting at a moderate level of 4 and peaking at 10 in April, indicating a shift to very high exposure. The months of May through August present the highest risk, with the UV Index consistently at an extreme 11, where the burn time reduces to just 10 minutes. Following this peak, September and October see a slight decrease, with the UV Index returning to 10 and 8, respectively, both still classified as very high. By November and December, levels drop back down to high and moderate categories with indices of 6 and 4, allowing for safer outdoor activities but still requiring caution. Residents and visitors should take protective measures, especially during the high-risk months of May to August, by wearing sunscreen, protective clothing, and seeking shade during peak sunlight hours to minimize the risk of UV 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 |
| McKinney | 4 | 6 | 8 | 10 | 11 | 11 | 11 | 11 | 10 | 8 | 6 | 4 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |