Do you take your goggles off your eyes during the ski day? Meaning do you lift them up on the lift etc or do they stay on the whole time?
Some reasons it might be happening:
Since you arent wearing a buff/gaiter around the face it's obviously not that.
1. Check helmets vents and goggle side vent to make sure they arent iced/snowed up.
2. Don't take your goggles off your face. You want to keep as much dry hot air mixed w vented cooler air in and condensate/moisture out. Lifting up your goggles flash cools them and carry condensate back to your face when you move them back.
3. DONT "BLOW UP" - that's when you let out a BIG BREATH - think like a small gasp - like you just ripped a ****ing donkey punch line and survived and you pivot Out and Go ****" That kinda breath if pushed upwards is a guaranteed fog out because you're pushing hot breath through your vents and under them which are flowing cold are through. Think yoga - calm steady breaths. Don't try to blow the poor piggies houses down.
4. Stay moving - you want to maintain air flow through your vents. That doesn't mean you need to go fast or faster or fastest or even almost fast or approaching fast. It means You need to maintain the flow of air through the Vents. Thats your speed but it must be moving.
5. Body temps - you're cooking inside my guy and that air is pushing up into and under the goggles. (Open your jacket and pant vents - even if it's snowing - be cool/comfortable not hot or approaching sweating). If you're building up body heat, releasing it as you move will keep you from chimney stacking heat up your torso and under your Vents.
6. If everything else fails: Cut a notch at the temples
Not really recommended unless you don't mind risking your goggles! Truly a last resort, but if there's nothing else that's working, carefully cut through the foam at the temples down to the frame, under the straps, using a small scissors. Taking out a chunk that's approximately two centimetres wide (narrower than your strap) shouldn't comprise the fit or feel of the goggles, but should dramatically increase the amount of hot air that can escape. This isn't recommended unless you're prepared to drastically alter your goggles and potentially fubar them.
7. DEFOG spray - won't really help if you're blowing up or chimney stacking from the body.
8. NEVER DEICE OR DEFOG THE INSIDE OF YOUR GOGGLES W YOUR GLOVES ON. YOULL REMOVE/TARNISH THE ANTIFOG COATING.
Hope one of these solves it. Please lmk.