Last updated: July 2, 2025
Understanding the UV Index is crucial for residents of Dorchester, Canada, as it directly impacts sun safety and skin health. With the potential for high UV levels, particularly between 11 AM and 2 PM, awareness can help prevent harmful sunburns and long-term skin damage. Dorchester's Dfb climate offers a balance of warm summers and cold winters, but during the sunny months, the UV exposure can be significant. Keep an eye on the daily UV Index to protect yourself and your loved ones from the risks associated with increased sun exposure.
The UV Index data illustrates a dynamic shift throughout the day, peaking in the afternoon hours. Starting at a mild 1 at 7 AM and 8 AM, the index climbs steadily, reaching a distinctive 3 by 9 AM. By 11 AM, it surges to 7, and the intensity escalates further with a peak of 10 at 1 PM—making it the most critical time for sun exposure. As the afternoon progresses, the index gradually declines, settling at 6 by 4 PM and tapering off to 1 by 7 PM. This data serves as a crucial reminder to take sunscreen precautions especially between 11 AM and 2 PM, when the sun’s rays are the strongest.
| 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 | 7 | high | 25 min |
| 12:00 | 8 | very high | 15 min |
| 13:00 | 10 | very high | 15 min |
| 14:00 | 9 | very high | 15 min |
| 15:00 | 8 | very high | 15 min |
| 16:00 | 6 | high | 25 min |
| 17:00 | 4 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, UV exposure fluctuates significantly. January sees a low UV Index of 2, while by February and March, it rises to 4 and 5, indicating moderate exposure and a burn time of 30 minutes. As spring progresses into April, the UV Index sharply increases to 8, categorized as very high, marking the beginning of high-risk months, which continue through May, June, July, and August with UV Index values reaching a peak of 10. Visitors and residents should take particular caution during these summer months, as burn time drops to just 15 minutes under peak conditions. September maintains a high risk with an 8 index, while the UV Index drops back to moderate levels in October (5) and November (4) before returning to low levels in December (2). To minimize the risk of UV exposure, it is essential for individuals to wear sunscreen, protective clothing, and seek shade, especially from late spring through early fall.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Edmonton UVI | 2 | 3 | 5 | 6 | 7 | 7 | 8 | 7 | 6 | 4 | 2 | 1 |
| Calgary UVI | 2 | 3 | 4 | 6 | 8 | 8 | 9 | 8 | 7 | 4 | 2 | 1 |
| Montreal UVI | 2 | 4 | 5 | 7 | 9 | 9 | 8 | 8 | 7 | 5 | 3 | 2 |
| Ottawa UVI | 2 | 4 | 5 | 8 | 9 | 9 | 8 | 8 | 7 | 5 | 3 | 2 |
| Toronto UVI | 2 | 4 | 5 | 8 | 9 | 9 | 9 | 9 | 7 | 5 | 3 | 2 |
| Dorchester | 2 | 4 | 5 | 8 | 9 | 10 | 10 | 9 | 8 | 5 | 4 | 2 |