Early failure of mechanically-stabilized earth (MSE) walls has been often attributed to the corrosion of galvanized steel soil reinforcements on facings. Galvanized steel is one of the most common materials used in the construction industry for its relatively compared to steels with higher corrosion resistance. A numerical model was developed to calculate the corrosion rate of galvanized steel in soil at three different stages of corrosion by considering key soil corrosion parameters such as resistivity, temperature, moisture content, pH, and oxygen availability. This paper focuses on the effect of temperatures relevant to the Canadian climate, and differential soil compaction (related to oxygen access) on the corrosion performance of MSE wall soil reinforcement and facings. Results indicate that the proposed model is suitable to be used for the service-life design and risk assessment of MSE walls and to determine the optimum zinc cover thickness.