the temp in an incubator fluctuates as a thermostat turnes the power to the heater off and on
there is always a swing in the air temp but its the egg temp that is critical
a human thermometer is also designed to measure in a fluid not air.
turn off your turner. out a pill jar with water in the turner under your vent hole for an hour and measure the temp
btw 100.8 wont hurt.
This is good advice, I tried using digital medical thermometers to verify my temps on my first hatch and it didn't work right, the temp on them was different by a long ways every time I took readings, I decided the medical thermometers weren't working right due to them not reading air temperature properly