period of time x stored in memory 20 u2014 fig1 as is shown at 38 if the time period e g five minutes has elapsed the wiping function remains dormant in this manner the system may prevent accumulation of snow during short parking periods without remaining continuously active since an objective is to prevent the freezing of precipitation and melted snow on the vehicle 39 s window the time period x should preferably be greater than the time it takes for the window to reach a freezing temperature if the elapsed time t is less than or equal to elapsed time threshold x processor 22 monitors temperature sensor 18 fig1 to determine if the window 39 s temperature is greater than a temperature threshold y e g freezing stored in memory 20 as is shown at 40 if the temperature of the window is below freezing it is assumed that accumulated snow will not melt and later freeze thus in this particular case wiping is not necessary if however the window 39 s temperature t is greater than the threshold i e t gt y processor 22 searches for moisture on the window as previously described to summarize the wiping phase corresponding to steps 44 46 and 48 may be reached by two path amp the first occurs when the system is enabled the vehicle is started the ambient temperature is below a threshold moisture is present on the window and the window is above a temperature i e steps 33 34 36 37 and 42 the second occurs within a predetermined period of time after an ignition cycle if the temperature of the.