Fiddling with new toys - got a $5 oven thermometer and a $40 meat thermometer. Set the oven to 350 - nice digital display, so it *should* be accurate and precise.
Update: Thought of a new test. We know how hot boiling water is - 212 degrees at sea level. Well, I'm 1,000 feet above that, but I pulled a pan of hot water (less dissolved solids) and set it to a rolling boil. The meat thermometer registered 212 degrees. So it is accurate and precise. The oven thermometer isn't submersible, so no way to test it - but comparing against the meat thermometer it appears to read within 10% or so, just slowly.