BeachFinder
Reading the UV scale
The UV index measures the intensity of ultraviolet radiation capable of damaging skin and eyes. It's an open scale, generally from 1 to 11+, read as follows:
| UV index | Level | What to do |
|---|---|---|
| 1 – 2 | Low | Protection not essential |
| 3 – 5 | Moderate | Protect yourself: sunscreen, hat, shade |
| 6 – 7 | High | Stronger protection, limit exposure |
| 8 – 10 | Very high | Avoid the sun in the hottest hours |
| 11+ | Extreme | Stay in the shade, maximum protection |
The key threshold to remember: start protecting yourself from index 3. In summer, on a French beach, the index frequently reaches 8 to 9 in the middle of the day, and higher in the mountains or the tropics.
What drives the UV index up
The UV index isn't fixed: it varies widely depending on several factors worth knowing.
- Time of day: the peak is around solar noon, when the sun is at its highest.
- Season: at its maximum in summer, but already significant in spring.
- Latitude: the further south you go, the higher it climbs.
- Altitude: it rises by about 10% every 1,000 metres.
- Reflection: sand, water, snow and concrete bounce the rays back.
Another trap: clouds only filter out part of the UV. Under a hazy or slightly cloudy sky, the index often stays high while the perceived heat drops, which tempts you to let your guard down.
Why the beach amplifies UV
At the beach, you catch more sun than elsewhere for the same index. Light sand reflects a significant share of the UV, and so does the water, so you're exposed from below on top of the direct radiation.
Getting wet is no protection: UV penetrates the surface to a depth of several tens of centimetres, and the cooling effect of the water completely masks the sensation of burning. So you can pick up a serious sunburn while swimming without feeling a thing. Even under a beach umbrella, you still receive UV reflected off the surrounding sand and water. That's why sunburn is so common by the sea.
The best shield: the right time of day
No sunscreen replaces avoiding the peak. The UV index is at its highest around midday, when the sun is high in the sky. A simple rule helps you picture the risk: the shadow rule. When your shadow is shorter than your height, UV is intense and you need to protect yourself seriously.
Schedule swimming and games for early morning or late afternoon, and set aside the 12pm – 4pm window for shade or sheltered activities when the index is high. Checking the day's UV index for your spot, as in BeachFinder, helps you set that timing before you leave.
Complete protection
Combine several measures, none is enough on its own:
- Sunscreen with a high factor (SPF 30 minimum, 50 for fair skin and children), applied generously 20 minutes before exposure and reapplied every 2 hours, as well as after each swim or towel-dry.
- Wide-brimmed hat and sunglasses filtering 100% of UV.
- Covering clothing or UV-protective lycra, especially for children and during long exposures.
- Shade (umbrella, tent, tree) during the most intense hours, keeping in mind that it doesn't block reflected UV.
Most people under-apply their sunscreen: you need the equivalent of about two tablespoons for an adult body.
Special cases: children and sensitive skin
Children's skin is thinner and more vulnerable, and childhood sunburns are among the main long-term skin-risk factors. A few stricter rules are called for:
- Infants should never be exposed directly to the sun; keep them in the shade and covered.
- Favour UV-protective clothing over sunscreen for young children, more reliable and easier to keep on.
- Fair skin, people with many moles and those on certain photosensitising treatments must be extra careful.
A sunburn is a burn: redness, heat and pain signal damage that's already done.