It is important to check that your temperature probe is working properly so you can rely on the readings. This is called calibration.
A digital temperature probe should be calibrated regularly.
A simple way to check a digital temperature probe is in iced water and boiling water.
The reading in iced water should be between -1°C and 1°C.
The reading in boiling water should be between 99°C and 101°C.
If the readings are outside of each of these ranges, the probe should be replaced or returned to the manufacturer to be calibrated. It is good practice to keep a record of when you have calibrated your temperature probes.