Last updated: May 3, 2025
Understanding the UV Index is crucial for residents of Grignon, France, where sunny days can translate to significant UV exposure. As the climate here falls within the Dfc zone, the risk of sunburn increases, particularly during peak hours when the UV levels soar to 9 around noon and early afternoon. Being aware of these UV levels is vital not only for preventing sunburn but also for maintaining overall skin health and reducing the risk of long-term damage. With knowledge of daily UV variations, you can take proactive steps to protect yourself and safely enjoy the beautiful outdoors in Grignon.
Starting from 07:00 AM, the UV Index remains low at 1, perfect for a morning stroll. As the sun climbs higher, the intensity gradually increases: reaching 3 by 09:00 AM and then escalating to 4 at 10:00 AM. The peak intensity occurs at 01:00 PM, with a striking UV Index of 9, suggesting it's vital to seek shade or apply sunscreen during this hour. The afternoon sees a slight decline, with values of 8 at 03:00 PM and 6 by 04:00 PM. As the day winds down, the UV Index drops back to 4 at 05:00 PM, and then gently falls to 2 by 06:00 PM, before settling back at 1 near sunset. It's a day to stay sun-smart!
| 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 | 4 | moderate | 30 min |
| 11:00 | 6 | high | 25 min |
| 12:00 | 8 | very high | 15 min |
| 13:00 | 9 | 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 |
As the seasons change, so does the UV Index, reflecting varying levels of sun exposure risk. From January to February, the UV Index remains relatively moderate, with a value of 3-4 and a burn time of 30 minutes. However, starting in March, the UV Index rises significantly, reaching high levels of 7 and subsequently peaking at 10 in June and July, marking the months of highest risk. April to August features very high UV Index ratings (8-10), with a critical burn time of only 15 minutes, making it essential for visitors and residents to take precautionary measures by wearing sunscreen, hats, and protective clothing during these months. With a decline in UV exposure in September (7) and further into the fall and winter months, the UV Index drops to moderate (5) in October and then to low (2) by December, allowing for safer outdoor activities. Overall, it is crucial to be vigilant, especially during the high-risk months of March through August, to ensure skin protection against harmful UV radiation.
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 |
| 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 |
| Grignon | 3 | 4 | 7 | 8 | 9 | 10 | 10 | 9 | 7 | 5 | 3 | 2 |