Dome Temp on a Weber Kettle vs Actual Cooking Grate Temp

all depends, r you cooking with the coals banked to one side and vent over the other, is it full of coals and grilling direct, all would have a lot to do with what the actual grate temperature is.

Well I cant compare on a dome....but this weekend. I had probe set at grate level, and one hanging down from the dome of my WSM. It was hanging down about 4 inches.

Was within a few degrees, which could have been the difference in probes. I should say I had it at the top grate, not the bottom one.

Its possible the higher temps of a grill procedure compared to smoking may yield a larger difference.

I have used a cheap regular Oven Thermometer on the grate for Temp's. They get smoke covered but you can clean them off.

On my Weber Silver and I have it set up for offset indirect cooking (coals on one side only and held back by some expanded metal), it is 75 degrees differrence between the farthest point on the grate and the dome.

22 1/2" Silver with about 60 briquettes on the side behind firebrick. Vents were just cracked open on the bottom and the top vent about 1/3 open. With a candy thermo stuck about 2 inches into the top vent , I had about a 60 degree difference between the dome and the grate.

i suggest spending $4 at wallyworld and get an oven thermometer; that way you'll
know exactly.

I have a grate thermo and don't really pay that much attention the the lid temps.I agree with the boy's depends on how you are cooking

Ditto the oven Thermo suggestion. When using my Weber Kettle, coals to one side, meat opposite then set the Thermo near meat--it kind of stands up like a picture frame if you can visualize that. Cheap to buy, and they last and dont seem to get out of whack temp wise. It will be filthy after a cook but after cooling and some elbow grease it cleans up fine.

On that note, you can also drop a stick Thermo in your dome lid holes at the same time. Then just get a feel for normally happens with the kind of heat you normally build for the time of meat you are cooking. A couple times and youll have a feel for your answer--based on the variables you create and that are unqiue (fire build, the outdoor elements, etc.)