I've got 4 thermometers. The one I'm planning on using in my incubator has sat comfortably between 99-100 during my first couple of test runs. I figured I ought to check it for accuracy and got out my brooder thermometer. Well, it did *not* agree with the digital one. Not even close. We were sitting in the mid 90s according to it. Hmmmm. So I got out my scientific thermometer. It agreed with the brooder thermometer. The first thermometer was off by a lot apparently! Then I figured I ought to calibrate the second two (the first is not calibrateable. awesome). I followed the crushed ice + water directions and lo and behold, my brooder thermometer read 2 degrees high and my scientific one read one degree high! So the first thermometer was even farther off than I'd originally thought! *however* I wanted to be absolutely sure. My scientifec thermometer read to the tenth of a degree, but it was finicky. I wasn't absolutely certain it'd be accurate for air readings, and it is kind of old and beat up (I use it as my meat thermometer now days. I can't use it as my main thermometer as it has a 10 minute shut off). My brooder thermometer had tic marks ever 2 degrees and my first thermometer only read to the whole degree. So I went out and bought another digital garden thermometer that read to the tenth. I was currently callibrating my first thermometer's humidity gauge (it's 3% low. No biggie) so it wasn't immedietly available to stick in the incubator. I put the new thermometer in, and the brooder thermometer, and the scientific thermometer. To my astonishment, suddenly the scientific thermometer and the new thermometer read similarly, and the brooder thermometer was two degrees *low*. I was also concerned because while the new thermometer was fairly steady (between 99.5 and 100.6) the scientific thermometer would range from 100.5 all the way down to 94! (the scientific thermometer displays real time up to the second temperature variances, and i guess the new thermometer is more suggish. In the same 60 second span the new thermometer will go from 100.0 to 99.5, and then back up to 100 while my scientific thermometer will go from 100.1 to 95.4 and back up to 99.8) So I finally finished my humidity calibration, and I figured I ought to see what my first thermometer would do. I put it in, and while it was coming up to temp, the temperature reading on the scientific thermometer plummeted and now agreed with the brooder thermometer, which read 96-98 while the new thermometer was still at 100.4. The first thermometer is still coming up to temp (reading 97 at the moment. same brand as the new thermometer, but different model. The first reads temp and humidity, the new reads only temp, but to a 10th of a degree) WHAT DO I DO BYCers? WHICH ONE DO I TRUST???? And now, just to drive me to start pulling out my hair, they're ALL reading 99-100. What the fuzzy??