Ok, I must confess... I have an iron thermometer (which I showed in the video) but frankly, I never use it. I just go by the results I'm getting.
I start with the dial on my iron at about a 10 O'clock position, and turn it slightly up or down depending on weather or not it is doing what I want it to do.
However, since you asked, I just checked. The iron I use most often is currently set just over 250 degrees and, when checked with the thermometer, it reads 260 degrees.
I'm honestly amazed that not only are either the dial or the thermometer accurate, but that they even concur with each other. I honestly thought one would read one number and the other would be anywhere from 20 to 50 degrees off
So there you have it. The last time I used my iron it was set at 260 degrees.