It is standard practice for the majority of digital thermometers to display a "LO" sign when turning the device on. This means "LOW TEMPERATURE". This is because these types of thermometers are made to measure Body Temperature, so when outside the body, the temperature is usually LOWER.

How do I fix the LO on my thermometer?

The 'Lo' or 'Hi' indications on the display mean that the temperature cannot be measured because the temperature is outside the temperature range. Press the on/off button to switch off the thermometer. Check if it is correctly positioned, press the on/off button again to switch it on, and re-start the measurement.

Why does my thermometer have an L?

The “L” means that the thermometer is at its lowest point and ready to take your temperature. It does not mean the battery is low. There is a separate low battery icon that will display all by itself when the battery is low. How do you change the thermometer from C to F?