Last updated: August 1, 2025
Understanding the UV Index is crucial for residents of Colby, United States, particularly given the area's BSk climate, which can lead to varying levels of sun exposure throughout the year. Awareness of UV levels helps in preventing sunburns and safeguarding skin health, as the sun can be surprisingly intense, especially around midday. With peak UV Index values reaching 11 in the early afternoon, it's essential for Colby residents to stay informed and take protective measures to minimize their risk of skin damage while enjoying the beautiful outdoors.
The UV Index begins its day gently, peaking at a maximum of 1 at 7:00 AM and holding steady until 9:00 AM when it climbs to 2. As the sun reaches its zenith, the index surges dramatically, hitting 5 by 10:00 AM and soaring to its peak of 11 at both 1:00 PM and 2:00 PM. This period marks the hours where sun protection is critical. As the afternoon progresses, the index gradually descends, dropping to 10 by 3:00 PM, then tapering off to 8 at 4:00 PM, and continuing its decline until reaching 2 by 7:00 PM. It's a vivid reminder that while the sun graces us with its warmth, vigilance against UV exposure is essential during peak hours.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 2 | low | 45 min |
| 10:00 | 4 | moderate | 30 min |
| 11:00 | 6 | high | 25 min |
| 12:00 | 9 | very high | 15 min |
| 13:00 | 10 | very high | 15 min |
| 14:00 | 10 | very high | 15 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 exhibits notable seasonal variations, with high-risk months typically occurring from March to September. During these months, the UV Index escalates to levels categorized as high (7), very high (8-10), and extreme (11-12), particularly peaking in June with an Index of 12, indicating an urgent need for protective measures. Burn times drastically reduce to as low as 10 minutes in the peak summer months, underscoring the importance for residents and visitors to prioritize sun safety. As a precaution, it is advisable to limit sun exposure during these high UV periods, especially between the hours of 10 AM and 4 PM. During lower risk months, notably January, February, and December, UV levels remain moderate, allowing for safer outdoor activities, though sun protection is still recommended as UV rays can cause cumulative skin damage over time.
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 |
| Colby | 4 | 5 | 7 | 9 | 10 | 12 | 11 | 10 | 9 | 6 | 4 | 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 |