Effect of ambient temperature simulating different weather conditions throughout the year has been investigated for insulators of different shapes under both polarities of applied direct voltage. The study revealed that for a given salinity of contamination solution the equivalent salt deposit density (ESDD) is strongly dependent on ambient temperature. This has been attributed to the change of solution viscosity. DC breakdown strength reduces by about 0.7% per degree Centrigrade rise in temperature. DC are characteristics are, however, independent of temperature. The observed temperature dependence of DC flashover voltage has been attributed exclusively to the change of residual resistance and a good agreement exists between the calculated and measured values. The influence of polarity in contamination flashover is equally effective throughout the investigated temperature range.