How to calibrate thermostate

[Bosque]

I just bought one of the Springfield thermometers that display the temp and humidity from Wal-Mart. How do you know if the temp is correct? Do you just take readings from other thermometers and take the average?
Thanks,
Bosque

 

[Intheswamp]

Compare it to a medical thermometer...the one's like you check for a fever with.

Best wishes,
Ed