Last updated: June 2, 2025
In Rennes, France, staying aware of the UV Index is crucial for protecting your skin and overall health. Understanding UV levels can help you prevent sunburn and reduce the risk of long-term skin damage, making it essential knowledge for both residents and visitors alike. Rennes experiences a Cfb climate, characterized by mild summers and rainy winters, but during peak summer months, UV exposure can become significant, with the Index soaring to 9 at its highest. Knowing when to take precautions—like applying sunscreen or wearing protective clothing—can make all the difference in enjoying safe and healthy outdoor activities.
The UV Index for the day reflects a dynamic rise in solar intensity as we move toward midday, peaking at 9 between 1:00 PM and 2:00 PM. Starting off gently, the day begins with a low UV rate of 1 at both 7:00 AM and 8:00 AM, making it safe for early morning activities. As the sun climbs higher, we see a steady increase, hitting 4 by 10:00 AM and reaching 5 at 11:00 AM. By noon, the UV Index escalates to 7, signaling that sun protection is becoming increasingly crucial. Post-peak hours show a gradual decline, with readings at 8 and 7 for 3:00 PM and 4:00 PM, respectively, before tapering off to a more moderate 2 by 7:00 PM. Therefore, it’s essential to stay vigilant during peak hours to safeguard against harmful UV exposure!
| 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 | 5 | moderate | 30 min |
| 12:00 | 7 | high | 25 min |
| 13:00 | 9 | very high | 15 min |
| 14:00 | 9 | very high | 15 min |
| 15:00 | 8 | very high | 15 min |
| 16:00 | 7 | high | 25 min |
| 17:00 | 5 | moderate | 30 min |
| 18:00 | 3 | moderate | 30 min |
| 19:00 | 2 | low | 45 min |
Throughout the year, UV exposure fluctuates significantly, with the highest risk months occurring from May to August, when the UV Index reaches levels categorized as very high (UV Index 8-9). During these months, the burn time drastically decreases to just 15 minutes, emphasizing the need for protection. Conversely, the low risk months of January, November, and December offer a safer environment with a UV Index of 2 and a burn time of 45 minutes. As such, visitors and residents should be particularly vigilant during peak summer months by wearing sunscreen, protective clothing, and seeking shade during peak sun hours, while enjoying the milder winter months with less concern for UV exposure.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Paris UVI | 2 | 3 | 5 | 6 | 8 | 9 | 8 | 8 | 6 | 4 | 2 | 1 |
| Rennes | 2 | 3 | 5 | 6 | 8 | 9 | 9 | 8 | 6 | 4 | 2 | 2 |
| Lyon UVI | 2 | 3 | 5 | 6 | 8 | 10 | 9 | 8 | 6 | 5 | 3 | 2 |
| Nice UVI | 2 | 4 | 6 | 7 | 8 | 10 | 9 | 8 | 7 | 5 | 3 | 2 |
| Marseille UVI | 2 | 4 | 5 | 7 | 9 | 10 | 9 | 8 | 7 | 5 | 3 | 2 |
| Toulouse UVI | 2 | 4 | 6 | 7 | 9 | 10 | 10 | 9 | 7 | 5 | 3 | 2 |