Last updated: July 2, 2025
Understanding the UV Index is crucial for residents of Rosny-sous-Bois, France, where sunny days can lead to significant UV exposure. This essential metric helps you gauge the strength of harmful ultraviolet rays, enabling you to take proactive measures against sunburn and safeguard your skin health. With Rosny-sous-Bois nestled in a temperate Cfb climate, it's important to be aware of the fluctuating UV levels throughout the day. For instance, during midday hours, UV Index values can spike to 8, meaning the risk of harm from unprotected sun exposure is high. Stay informed and protect your skin with proper precautions!
The UV Index today presents a dynamic range, peaking during the midday hours. Starting off gentle in the morning, with 1 at both 07:00 and 08:00, the index gradually climbs to 2 by 09:00. As the sun reaches its zenith, the intensity soars, hitting 6 at 11:00 and peaking at an impressive 8 from 13:00 to 15:00. This indicates a critical time for sun protection, as the index then begins its decline, dropping to 6 by 16:00 before tapering off further to 3 by 18:00 and 2 at 19:00. Stay safe and enjoy the outdoors while being mindful of the sun’s rays!
| 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 | 7 | high | 25 min |
| 13:00 | 8 | very high | 15 min |
| 14:00 | 8 | very high | 15 min |
| 15:00 | 8 | very high | 15 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 levels vary significantly, with the highest risk months occurring from May to August, where the UV Index reaches a peak of 9 in June and remains at 8 during July and August, indicating a very high exposure category and a critical burn time of just 15 minutes. In contrast, winter months see much lower UV levels, with January and November registering a UV Index of 2 and December dropping to 1, categorized as low exposure. Visitors and residents should exercise caution during the high-risk months by minimizing sun exposure, wearing protective clothing, and applying sunscreen regularly, particularly between late spring and early fall when UV radiation is at its strongest.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rosny-sous-Bois | 2 | 3 | 5 | 6 | 8 | 9 | 8 | 8 | 6 | 4 | 2 | 1 |
| Paris UVI | 2 | 3 | 5 | 6 | 8 | 9 | 8 | 8 | 6 | 4 | 2 | 1 |
| 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 |