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Outdoor 26 February 2016 Back to list
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How to choose your high-mountain sun protection

While the risks linked to the mountains themselves may be obvious, those caused by exposure to the sun at high altitudes are more difficult to understand. Julbo sheds some light on the subject.

How to choose your high-mountain sun protection

The dangers of the sun in high-mountain environements

Exposure to solar radiation increases on average by 10% (between 4 and 16%) with every 1,000 m of altitude, and the UVB light it contains is particularly dangerous.

In addition, the snow often present in the mountains reflects between 80 and 90% of solar radiation compared with 20% on non-snowy ground.

The intensity of solar radiation is therefore 1.5 times greater at 2,000 and 2.5 times greater at 4,000 m than at sea level.

It should be noted that solar radiation is 25% greater at the autumn equinox than the spring equinox when the ozone layer is thicker.

The ozone layer varies in thickness depending on where you are in world and therefore offers differing degrees of protection.


In cloudy conditions the sun is still dangerous in the mountains. You should not count on overcast skies to protect you as they provide 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 altitude, in overcast conditions, you may frequently find yourself in the upper layer of the clouds. The radiation here is intense through the effects of light diffraction. The risks are therefore even higher than in fine weather.

Julbo sun solutions

We have developed a range of products specially adapted to these extreme conditions :

In terms of lenses:

  • Spectron 4: polycarbonate lens (VLT* :5%). Designed to offer powerful protection for mountain trekking and mountaineering
  • Cameleon: Category 2 to 4 NXT© photochromic lens (TLV*: 20-5%). The brown tint and filtration level have been designed to offer the best performance for trekking and mountaineering. NTS technology guarantees a constant photochromic range, whatever the outside temperature.
  • Zébra: Category 2 to 4 NXT© photochromic lens (TLV*: 42-7%). Lighter than the Cameleon lens and suitable for skiing and trail running. Offers good protection at low temperatures in high-mountain environments.


 In terms of frame:

A good frame must therefore provide:

  • Total coverage / protective side shields
  • A pronounced curve
  • Excellent grip
  • Ideally a headcord

Our high mountain sun protection

EXPLORER : High-tech for the highest mountains

The highest mountains and extreme conditions bring out the best in these sunglasses developed in collaboration with the elite climbing school in Chamonix.

The Explorer takes glacier sunglasses to the next level: lenses with impressive protection, coverage from damaging UV rays, an anti-fog ventilation system and side shields to stop wind and snow getting in.

TREK : Fast and light

Trek's mission is to provide highly technical but light equipment for moving fast in extreme environments and achieving optimum performance.

It combines the fundamental principles of mountaineering glasses with the lightness and ergonomics of speed sport sunglasses.

The side shields block radiation in high glare environments such as glaciers and deserts, while the suspended lens ensures clear vision and good ventilation.   

BIVOUAK : Let's feel the magnetic attraction

Outdoor sports have met their match with the Bivouak, solar protection for any condition. With wide Cameleon lenses, optimal coverage, magnetic protective wings that can be added in a split become one with the elements.

MonteRosa : Feminine from peaks to streets

For those ladies who explore the summits yet also enjoy the hustle and bustle of urban life, Julbo presents the Monta Rosa. With removable shields, high protection lenses and a curved ergonomic shape, the MonteRosa offers adaptability, versatility and complete protection.

MonteBianco: From mountain to valley

A great classic for mountain lovers on familiar terms with the peaks… but who also return to the valley! Ideal for medium to large faces, the removable protective side shields offer perfect adaptability to climatic conditions. Lightness, technical excellence and high protection are combined with style and simplicity on this model.

TENSING : A whole new look in the mountains

The Tensing provides novice mountaineers the choice they need when looking for protective eyewear. The ultra-wrap profile design guarantees maximum protection against high altitude, as well as superior ventilation. The dual injected frame strategically combines a strong outer material with a highly flexible inner design for comfort against the face.

Cette lunette a été conçue pour que les alpinistes amateurs puissent pratiquer en toute sécurité, grâce à leur excellent rapport qualité/Prix.

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