Definitely Calibrate. I think jddevin meant to say 212f at sea level. I know people calibrate at cold and hot, if there is a difference I would go with the more accurate one at boil. I have had thermometers calibrate at 32 and read diff temps at boil. Since we tend to work on the hot side that is what I focus on. Definitely know what temp you h2o boils at you elevation 204f in Denver. I like my dial thermometer because it does not change as quickly giving a more average temp of the mash. My super-acurate digital reads different #'s in different parts of the mash.