You should have configured your AC before you started driving.
I haven’t had windows fog up during a drive spontaneously since forever ago when AC became standard in even cheap vehicles since they dry the air.
You’ve never driven in a humid tunnel, or live in a place with changing weather do you?
Oh I do, we have almost 200 days of precipitation yearly, and temperatures fluctuating wildly between days all seasons of the year.
I’m driving. There is not a drop of rain in the sky. 2 hours into my drive it starts raining and my windows fog up. Your answer is I should have turned on the defrost before I left. Interesting. Against reason and human nature. But interesting.
What kind of shit-buckets are you people driving that requires you to turn on defrost just because it starts raining!?
I regularly drive in conditions that go from sunny to rainy, or even sunny to snow/slush…that’s pretty much all our weather is where I live. I never have to start defrost mode while driving, ever. I use defrost to defrost and remove ice from the the car before I start driving, the AC keeps everything fine without me adjusting anything no matter the change of conditions while I’m driving.