The time evolution of the Indian Ocean warm pool, studied using a global high-resolution general circulation model, shows strong seasonality. The warm pool has the largest spatial extent during April-May, and least in December. The spatio-temporal variability of its surface area is tightly coupled to incoming solar radiation, except during the summer monsoon (June-September) when Ekman dynamics dominate. The vertical extension of the warm pool, on the other hand, appears to be controlled by the equatorial currents. The heat budget of the warm pool shows that the local heat storage is entirely accounted for by the surface heat flux and advection (horizontal and vertical) in all the three regions, viz. northern, equatorial and southern, considered in the study. Surface heat flux has a dominant role in determining the local heat storage and SST in the northern region, while advection plays an important role in equatorial region. In the southern region both surface heat flux as well as advection are equally important in regulating the local heat storage and SST.