I can't find anywhere that shows the temperature of smoke- an internal temp of a cigarette or pipe bowl, sure. Smoke, I'd love to see those results.The temperature of the smoke when it comes out of the mouthpiece and into the mouth has been measured and it's on par with the temperature of hot coffee.
It's only hotter when the unseasoned smoker sips/puffs forcefully, and/or when the pipe is lit/relit, but it hardly ever passes the 373 K mark. I've never heard of a pipe smoker ending up in the ER due to a forceful puff.
Most of my burns have happened from improperly lighting the pipe.
Heat is definitely a major factor, but not the only one. Other factors, like pH cause and/or compound the problem. Aaaand... everyone's mouth has a different pH—which in turn is due to many factors: diet, body chemistry, genetics, ailments, et cetera.
This thread was also inconclusive. We have a tongue bite thread, about every year. As Ashdigger states here, it's way more fun speculating and second-guessing than actual measurement.
Smoke Temperature :: General Pipe Smoking Discussion
This thread is exactly why I abandoned my thoughts of testing. Its way more productive and interesting second guessing and talking shit.
pipesmagazine.com