At about 55 kilometers (where it's close to 25 degrees C and maybe 2/3 of standard air pressure) there are clouds of sulfuric acid. I believe you can avoid them

At about 55 kilometers (where it's close to 25 degrees C and maybe 2/3 of standard air pressure) there are clouds of sulfuric acid. I believe you can avoid them by going higher, but then you lose the appeal of having earthlike temperature and pressure.