There's so much unheated air accompanying the vapour, through the air vents, that my recollection of vaping is it wasn't even warm. I'm sure there is a temperature difference after the vaporiser, but I never noticed it. Completely unlike smoking where you often noticed it was hot.

Sounds like something for a Youtuber to measure. :)

I never tried a Juul, just regular mods and vape pens if that makes a difference.

Interesting. I always thought hot air was the mechanism that causes a cough. Maybe it is just the lack of oxygen.

The proportion of VG and PG, vegetable glycerine and propylene glycol, decides how hard it is on the throat. Known as "throat hit" on vaping sites. More PG gives more throat hit - it feels harsher, and more chance of a cough, but fewer clouds. I used to prefer the high VG liquids as I thought the throat hit part of the bad of smoking that I wanted to quit.

Maybe some of the flavours have impact too, I don't know. One thing that is different is it's "just" a cough from immediate irritation. None of the horrible green and yellow crap coming up from a coughing fit next morning that you got from tobacco.

That's ignoring Juul which works differently, I have no idea what goes on in those.

It's more likely particles that causes coughing.