I am wondering what the difference is between the dome thermometer vs grate temp, i have heard as much as 25deg or there abouts, yes, no?
yes
That's generally what I run on my WSM. Sometimes it can be as much as 40 at times but I don't think there is enough to do damage to what you are smoking/cooking. I'm using an iGrill when I compare grate vs dome.
Ron, that was my experience with the thru-the-handle thermos on the older grills. But I find the newer style thermos in the lid to be much more accurate-- more like 15 to 20 degrees. Close enough that I stopped pulling out my Maverick for most kettle cooks.
Early in the cook when the meat is cold, the disparity is the greatest. As the meat heats up, the grate and lid thermometers will approach each other.
Upshot is that if you control to a constant lid temperature reading, you will start out a little hotter while the meat is cold and then drop down as the cook proceeds. I think that is probably a Good Thing and may even be what Weber intended. Otherwise they could have put the thermometer in the mid-section.
(I'm speaking of the WSM - the same may be true of a kettle.)
Good to know thanks all for the info.