The stochastic modeling of the ⁶⁰Co γ/fast-electron radiolysis of the ceric-cerous chemical dosimeter has been performed as a function of temperature from 25–350°C. The system used is a dilute solution of ceric sulfate and cerous sulfate in aqueous 0.4 M sulfuric acid. In this system, H^• (or HO₂^• in the presence of dissolved oxygen) and H₂O₂ produced by the radiolytic decomposition of water both reduce Ce⁴ ions to Ce³ ions, while ^•OH radicals oxidize the Ce³ present in the solution back to Ce⁴ . The net Ce³ yield is given by G(Ce³ ) = g(H^•) 2 g(H₂O₂) – g(^•OH), where the primary (or “escape”) yields of H^•, H₂O₂ and ^•OH are represented by lower case g's. At room temperature, G(Ce³ ) has been established to be 2.44 ± 0.8 molecules/100 eV. In this work, we investigated the effect of temperature on the yield of Ce³ and on the underlying chemical reaction kinetics using Monte Carlo track chemistry simulations. The simulations showed that G(Ce³ ) is time dependent, a result of the differences in the lifetimes of the reactions that make up the radiolysis mechanism. Calculated G(Ce³ ) values were found to decrease almost linearly with increasing temperature up to about 250°C, and are in excellent agreement with available experimental data. In particular, our calculations confirmed previous estimated values by Katsumura et al. (Radiat Phys Chem 1988; 32:259–63) showing that G(Ce³ ) at ∼250°C is about one third of its value at room temperature. Above ∼250°C, our model predicted that G(Ce³ ) would drop markedly with temperature until, instead of Ce⁴ reduction, Ce³ oxidation is observed. This drop is shown to occur as a result of the reaction of hydrogen atoms with water in the homogeneous chemical stage.