My incubator came with a calibrated thermostat and thermometer so I am pretty confident the temp inside the incubator is running at 100 degrees. Just to check I bought a digital thermometer and put it inside so I could see it. It's been running around 98-99 degrees. So I bought another with an inside/outside capabilities (it has an exterior probe so it reads 2 temps at once). I put it inside the incubator. Now I have 4 different temperature readings. And wouldn't you know it none of them the same. The digitals all read just a bit low. One reading almost 2 degrees low. The one closest to the calibrated thermometer is still low by 0.5 degrees. After reading how critical it is to maintain 100 degrees for a successful hatch I'm a bit concerned that something is a miss. Maybe the calibrated thermometer has drifted and is now off by a few degrees. I was also thinking about all the home bator builders here and how many report unsuccessful hatches. Maybe the cheap thermometers are doing many folks in. If they have an accuracy of +/- 1 or 2 degrees that is way more than enough to be a serious problem.