It is important to remember that, even in cloudy conditions, the sun is still dangerous in the mountains.
You should not count on overcast skies to protect you as cloud cover provides only limited filtration. While UV light can be stopped by some clouds (alto-cumulus), cirrus clouds have no filtration effect at all.
50% of the sun's radiation passes through fog. It is therefore necessary to protect yourself in the mountains, even when conditions are cloudy.
At high altitudes in overcast conditions, you may frequently find yourself in the upper layer of the clouds. The radiation here is intense due to the effects of light diffraction. The risks are therefore even higher than in fine weather.
Julbo has developed a range of products specially adapted to these extreme conditions that combine Category 4 lenses, wraparound frames and protective side shields. Check out our mountain collection