When racing in cool/ damp weather.
Last year i left my driver window down a bit, didnt notice, rained. Guess inside of car had moisture. Couldnt see out of car racing that night in cool weather. Pulled the plug. Sucked.
Have had it happen on other occasions too.
What works ?
Have heard everything from Dawn dish soap to buying a hair dryer with 12v plug, and that RainEx doesn't work very well

Move out west we don't have that issue

Keep in mind that the "fog" is moisture. It cannot be prevented. Any anti-fog coatings merely decrease the surface tension, causing the moisture to form larger globs of water - hence no "fog". The best solution is warm, moving air ... like a defroster !!!

All true. And Rain-X does work - just not as people expect it to.

Look online there are small 12v RV defrost fan heaters that could be easily used. Another thing my buddy did years ago to his race car. He used 2 marine engine bay bilge fans. Inside the car and duct it out a side 1/4 Lexan window. To pull out burn out smoke and other fumes. Worked really well

I just turn the defroster on, the heat comes in handy too.

one trick is to burn a candle. I had one that was rather large that worked well. I also have a bus fan mounted on the passenger side to circulate the air. Birdtracker

Rains makes a anti fogger. Spray it on wipe off. Stays on your window for weeks. I’ve been using it for years in my street rods works great. Most auto parts sell it.

Nitrous purge helps a lot

We have a "fogging up" problem at one of the tracks that I run, especially in the later rounds (after about 9 pm). Not only does the inside fog up, but also the dew falls on the outside, and you can't see out at all with lexan w/s & windows. What I do is to put a small electric heater inside the car, close the door AND cover the w/s & roof with an old blanket. I do this as soon as I get back from a run and leave it there until I'm called back to the lanes. Pretty nice at 2am, 50* outside and damp, to get into a nice warm car that you can see out of. Get back to the staging lanes, and everyone else trying to see where they're going.

Brian

Add a real heater and back off the burgers to compensate. Soooo much nicer than ANY alternative