Defog Windshield without dehumidifying

The quick answer is NO. Warm humid air recirculating around will simply lead to refogging of the glass. Add to that the air you and your pup are exhaling into an enclosed space with cold glass all around you. It's a lot worse than a foggy bathroom mirror because the other sided of the glass is much colder. It's simple physics - same reason a cold beverage glass sweats.
Bottom line; you need to lower the humility of the air within the cabin to keep the glass from refogging.

YMMV

 

Cold air outside, warm air inside.
Are you using the defogger button so it blows A/C air on the windshield?

You can also use a rag to wipe the windshield off...

 

Does spitting on it first help with the effectiveness, like with a diving mask?

 

Has that changed over the generations? I'm pretty sure my Gen 5 doesn't automatically crank up the A/C on defrost, but I'll check the manual.
How about a mix of defrost and front vent? Is there a position for that?

 

There are a few anti-fog products in the market, but due to the high humility - you'll constantly be reapplying it.

 

It's not like you have it on recirc, right?

 

You actually need it set for recirculate to dehumidify the cabin and prevent other glass in the cabin from refogging. I'm surprised that a lot of people don't know that. While your windshield may be clear and your rear glass, only if you've got the defogger ON back there too. All your side glass will fog up, so your door mirrors would be useless. The good thing is that you won't see that T-bone coming at you. Or the cars in the lanes next to you.

FWIW; it's raining today where I'm at. HVAC in manual mode, lo fan speed temperature set for 68F; didn't have to defog anything nor did I have to turn-on any defogger.

 

Gee, I wonder how people lived without air conditioning in their cars.

 

I'm a bit bougie; I had a swamp cooler option in my 1950 Oldsmobile. The heater core in that would turn the interior into a sauna. Manual doors, no fancy solenoid controlled mixer doors. DMV made me install seat belts on a safety check - told me they were missing. I told them that wasn't an OEM option, when it was new....