How much warmer is the ocean surface than the atmosphere directly above it? The present study offers a means to quantify this temperature difference using a conceptual nonlinear one-dimensional global energy balance coupled ocean–atmosphere model ("Aqua Planet"). The significance of our idealized model, which is of intermediate complexity, is its ability to obtain an analytical solution for the global average temperatures. Our analytical model results show that, for the present climate, predicted global mean ocean temperature is 291.1 K whereas surface atmospheric temperature above the ocean surface is 287.4 K. Thus, the modeled surface ocean is 3.7 K warmer than the atmosphere above it. Temporal perturbation of the global mean solution obtained for "Aqua Planet" showed a stable system. Oscillation amplitude of the atmospheric temperature anomaly is greater in magnitude than those found in the ocean. There is a phase shift (a lag in the ocean), which is caused by oceanic thermal inertia. Climate feedbacks due to selected climate parameters such as incoming radiation, cloud cover, and CO2 are discussed. Warming obtained with our model compares well with Intergovernmental Panel on Climate Change's (IPCC) estimations. Application of our model to local regions illuminates the importance of evaporative cooling in determining derived air–sea temperature offsets, where an increase in the latter increases the systems overall sensitivity to evaporative cooling.