Last updated: June 2, 2025
Understanding the UV Index is crucial for residents and visitors of Cornwall, Canada. With summer temperatures rising and sunny days becoming more frequent, being aware of UV levels is essential for sunburn prevention and overall skin health. During peak sun hours, particularly around noon, the UV Index can reach high values of up to 9, signifying a high risk of harm from unprotected sun exposure. Given Cornwall's climate, categorized as Dfb, individuals should be vigilant about the potential for intense UV rays, especially in the warmer months. Staying informed and taking appropriate precautions can ensure a safe, enjoyable time in the sun!
The UV Index reveals a dynamic day of sun exposure, starting with a gentle 1 at 07:00 and gradually ramping up as the morning unfolds. By 09:00, it climbs to 4, reaching a more noteworthy 6 at 10:00. As the sun reaches its zenith, the UV Index peaks at 9 during the crucial hours of 12:00 and 13:00, indicating a high risk of harm from unprotected sun exposure. The intensity begins to wane after 14:00, settling to 7 at 15:00 before gradually decreasing to 1 by 19:00. Remember to protect your skin between 11:00 and 14:00 when the sun’s rays are at their most dangerous!
| 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 | 7 | high | 25 min |
| 12:00 | 9 | very high | 15 min |
| 13:00 | 9 | very high | 15 min |
| 14:00 | 8 | 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 |
As the seasons change, so do the UV index levels, reflecting varying risks of sun exposure throughout the year. Late spring and summer present the highest UV indices, peaking at 9 from May to July, categorized as very high, with a burn time of just 15 minutes. This indicates that April through August are the critical months to be vigilant about sun protection, especially for those engaging in outdoor activities. Conversely, the UV index is at its lowest in January and December, where it drops to 2 with a low exposure category and a burn time of 45 minutes. Visitors and residents should prioritize sun safety during the high-risk months—consider wearing protective clothing, applying sunscreen regularly, and seeking shade during peak sunlight hours.
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 |
| Cornwall | 2 | 4 | 5 | 8 | 9 | 9 | 9 | 8 | 7 | 5 | 3 | 2 |
| Toronto UVI | 2 | 4 | 5 | 8 | 9 | 9 | 9 | 9 | 7 | 5 | 3 | 2 |