Can you make that question more specific?. Do you mean how will you know if Zener break down has happened or how will you measure the Zener current or voltage?
Zener diode which is dependent on zener effects, is not depend on temperature. So changing the temperature will not affect the zener effect. But avalanche effect, that is the effect of excited electron from valence band to conduction band duo to high electric field, is temperature dependent.
Because of high electric field, the valence band jump from valence to conduction band and the prior electron start to impact ionization effect.
As the electron in valence band can excite by thermal energy and jump to conduction band, the avalanche effect is temperature dependent.
So if you want to measure the avalanche effect in semiconductor, you have to consider the temp.
For measuring the avalanche effect, you have to transfer the electron that will produce by avalanche effect of your device to a capacitor that is connected to the device, and measure the voltage of capacitor. As you know the voltage and well capacity of capacitor, you can calculate the charge of capacitor, then by dividing the charge of capacitor by the charge of on electron, can understand the number of electron.
If the number of electron, in high voltage applied is too many, more than for example 100 …, the effect that happen is avalanche effect. But if the number of electron is a few, it could be due to tunneling effect.