Abstract Injection-induced fractures in large-scale CO2 storage projects may not be permitted by regulators. Injection pressure is the first-order determinant of whether fractures are initiated, but another important factor is temperature difference between formation and injected fluid. This difference causes thermoelastic stress that reduces the fracturing pressure. Accurate prediction of bottomhole temperature is therefore important to predict injection-induced fractures. In this work, we improve the steady-state heat transfer model for a CO2 injector by accounting for dependency of heat transfer coefficient on injection rate. The improved model predicts bottomhole temperature much more accurately across a large range of dynamic injection rates measured at Cranfield.