Excessive switching voltages in electrochromic devices cause rapid degradation in performance. Optimisation of switching voltages is therefore critical in order to realise the maximum possible device lifetime and to produce a commercially reliable product. The magnitude of the voltages required to colour and bleach a device are temperature dependent, with lower voltages being required at higher temperatures. In real applications, electrochromic devices may attain temperatures as high as 70 degrees C. Use of the room temperature switching regime at elevated temperatures may impose an overvoltage on the device, which can significantly reduce both lifetime and optical performance. A voltage limited constant current charge injection technique was used to cycle sol-gel deposited WO3 films at elevated temperatures. The voltages required for colouring and bleaching at these temperatures were determined and correlated with the level of coloration achieved. The results show that the variation in switching voltages is significant and, therefore, inclusion of temperature in the switching algorithms is necessary to achieve maximum lifetime for electrochromic devices.