Last updated: May 3, 2025
Understanding the UV Index in Rennes, France, is essential for maintaining skin health and preventing sunburn, especially during the warmer months. With a Cfb climate that features mild summers and frequent cloud cover, locals and visitors alike may underestimate the potential for UV exposure. On sunny days, peak UV levels can reach as high as 8 in the early afternoon, highlighting the need for awareness and precautionary measures. By staying informed about the daily UV Index, you can protect yourself from harmful effects while enjoying the beautiful sights that Rennes has to offer.
The UV Index throughout the day presents a clear trajectory, starting low in the early hours. From 07:00 to 09:00, the UV Index remains at a safe 1 to 2, offering minimal sun exposure risk. As the day unfolds, a notable spike occurs between 10:00 and 13:00, with values climbing to a peak of 8. This indicates a heightened need for sun protection during these late morning to early afternoon hours. Post 14:00, the Index begins to gradually decline, yet remains moderately elevated, dropping to 5 by 17:00 before settling back to 2 by 19:00. Plan your outdoor activities wisely and stay protected, especially during those 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 | 3 | moderate | 30 min |
| 11:00 | 5 | moderate | 30 min |
| 12:00 | 6 | high | 25 min |
| 13:00 | 8 | very high | 15 min |
| 14:00 | 8 | very high | 15 min |
| 15:00 | 7 | high | 25 min |
| 16:00 | 6 | 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 |