WHY DO GOGGLES FOG UP? (THE SCIENCE EXPLAINED)

Hey all, Tanner here (if this is your first time at the Lodge, check out our past ones here).


At Glade, we build our goggles to handle the harshest conditions in the mountains, but even the best optics can’t escape the laws of physics. Fogging is something every skier and rider has battled or at least heard about, and while lens tech plays a role, the root cause often just comes down to science and yes, sometimes to a few fog-inducing habits on our part. Let’s break it down.

The Science of Fog

Fogging starts with one simple ingredient: moisture. Your body heat, sweat, and breath create warm, humid air inside your goggles. At the same time, the outer lens is exposed to much colder mountain air. When that warm, humid air collides with the colder lens surface, the vapor rapidly cools and condenses into tiny liquid droplets. Those droplets scatter light, forming the cloudy film we call fog.

In short: warm, moist air + cold lens = condensation.

Why It Gets Worse on the Mountain

Several factors can tip the balance toward more fog:

 

  • Poor ventilation → If airflow through the goggle is blocked by poor fitting goggles or with a face mask, then the warm, humid air gets trapped, which increases the internal and external air differential.

  • Overheating → Skiing hard, skinning uphill, or overdressing adds extra body heat and sweat, which turbocharges humidity inside the lens.

  • Face coverings → Buffs and balaclavas if worn improperly often redirect your warm breath straight up into your goggles, increasing heat and moisture content.

  • Snow buildup → Snow melting on the goggle foam introduces extra moisture. Especially on powder days.

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How Tech Helps (and Where It Can’t)

Modern goggles, including ours, are designed with anti-fog coatings, dual-pane lenses, and carefully engineered ventilation to slow fog formation. But here’s the reality: no goggle tech can fully out-engineer physics. The way you use your goggles plays a massive role in whether they stay clear or not.

Avoiding Fog: Habits to Watch

To minimize fogging, check out our fogging FAQ page. Or, for a quick rundown, here are a few key guidelines:

 

  • Don’t touch the inside lens. The anti-fog treatment applied at the factory is the best defense you have — once it’s rubbed off, it’s gone for good.

  • Keep them on. Taking your goggles off in the lift line or lodge exposes the inside lens to cold humid air and can accelerate fogging.

  • Dry them out completely. Let your goggles dry inside overnight, not in a cold car or in a wet bag with your boots.

  • Dial your layering. Overheating adds to the problem. Dress smart so you don’t sweat unnecessarily.

  • Defog smart. If your lenses fog, take the goggles off completely and let them clear — avoid wiping.

At the end of the day, fog is the product of physics meeting mountain conditions. With the right tech and a few small habit shifts, you can keep your vision clear and your turns sharp.

-Tanner

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