Wire arc additive manufacturing (WAAM) has attracted significant attention in the manufacturing industry due to its ability to economically produce large-scale metal components with a relatively high buy-to-fly ratio. To date, a wide range of engineering materials has become associated with this process and application. As an electric arc and additive deposition have been combined, the complex heat transfer and thermal cycles cause several material processing challenges in WAAM. This study provides a comprehensive overview of the thermal characteristics during a WAAM process and identifies the thermal behavior effects on the process stability, geometrical accuracy and material properties of the deposited part. An innovative method for controlling thermal profiles during the build process is proposed and discussed, taken in to account the requirement of the various alloys. This paper concludes that the broad application of WAAM still presents many challenges, and these may need to be addressed in specific ways for different materials in order to achieve an operational system in an acceptable time frame. Highly accurate control of thermal profiles in deposition to produce defect-free and structurally sound produced parts still remains a crucial effort into the future.