The wettability of a formation is defined as the tendency of one fluid to spread on a surface in competition with other fluids which are also in contact with it. However, the impact of temperature on wettability in an aquifer and the modification of relative permeability curves based on the temperature variation in aquifers is not well covered in the literature. This study redresses this dearth of information by investigating the impact of temperature on wettability distribution in a reservoir and updating the relative permeability curves based on its temperature propagation. The impact of the latter is studied in relation to the solubility of CO(2) injected into an aquifer using the numerical methods (i.e. ECLIPSE). If the CO(2) injected has a temperature higher than the formation geothermal temperature, it can change the wettability of the formation further to a more CO(2) wet condition. This increases the risk of leakage and also changes the relative permeability curves as the CO(2) moves through the reservoir, a situation that needs to be considered in reservoir simulations. The results show that updating and modifying the relative permeability curves with temperature variation in an aquifer can increase the amount of CO(2) dissolution there.