An apparatus for detecting or predicting fog on an interior surface of a window of a compartment of a vehicle, the apparatus comprising: a processor; at least one first sensor coupled to the processor; a fog protection system; characterised in that the apparatus further comprises: at least one second sensor coupled to the processor; and a computer-readable storage medium coupled to the processor and having computer-readable program code stored therein that, in response to execution by the processor, causes the apparatus real-time during operation of the vehicle to: receive at least one measurement from the first sensor, and from the measurement identify or calculate a dew-point temperature in the compartment of the vehicle including the window (124, 126); calculate a surface temperature of at least a portion of the interior surface of the window (124, 126); detect or predict fog on the interior surface of the window (124, 126) in the event the dew-point temperature is at, near, or above the surface temperature of the interior surface of the window (124, 126); receive at least one measurement from the at least one second sensor, the measurement being of an intensity of a light beam reflected off the interior surface of the window (124, 126); and detect fog on the interior surface of the window (124, 126) in the event the intensity is below a predetermined threshold; and automatically activate the fog protection system to reduce or prevent fog on the portion of the interior surface of the window (124, 126) in the event fog is detected or predicted according to the measurement of the at least one first sensor or the measurement of the at least one second sensor. a processor; at least one first sensor coupled to the processor; a fog protection system; characterised in that the apparatus further comprises: at least one second sensor coupled to the processor; and a computer-readable storage medium coupled to the processor and having computer-readable program code stored therein that, in response to execution by the processor, causes the apparatus real-time during operation of the vehicle to: receive at least one measurement from the first sensor, and from the measurement identify or calculate a dew-point temperature in the compartment of the vehicle including the window (124, 126); calculate a surface temperature of at least a portion of the interior surface of the window (124, 126); detect or predict fog on the interior surface of the window (124, 126) in the event the dew-point temperature is at, near, or above the surface temperature of the interior surface of the window (124, 126); receive at least one measurement from the at least one second sensor, the measurement being of an intensity of a light beam reflected off the interior surface of the window (124, 126); and detect fog on the interior surface of the window (124, 126) in the event the intensity is below a predetermined threshold; and automatically activate the fog protection system to reduce or prevent fog on the portion of the interior surface of the window (124, 126) in the event fog is detected or predicted according to the measurement of the at least one first sensor or the measurement of the at least one second sensor. receive at least one measurement from the first sensor, and from the measurement identify or calculate a dew-point temperature in the compartment of the vehicle including the window (124, 126); calculate a surface temperature of at least a portion of the interior surface of the window (124, 126); detect or predict fog on the interior surface of the window (124, 126) in the event the dew-point temperature is at, near, or above the surface temperature of the interior surface of the window (124, 126); receive at least one measurement from the at least one second sensor, the measurement being of an intensity of a light beam reflected off the interior surface of the window (124, 126); and detect fog on the interior surface of the window (124, 126) in the event the intensity is below a predetermined threshold; and automatically activate the fog protection system to reduce or prevent fog on the portion of the interior surface of the window (124, 126) in the event fog is detected or predicted according to the measurement of the at least one first sensor or the measurement of the at least one second sensor.