Different types of interfacial conditions between a porous medium and a fluid layer are analyzed in detail. Five primary categories of interface conditions were found in the literature for the fluid flow at the interface region. Likewise, four primary categories of interface conditions were found in the literature for the heat transfer at the interface region. These interface conditions can be classified into two main categories, slip and no-slip interface conditions. The effects of the pertinent parameters such as Darcy number, inertia parameter, Reynolds number, porosity and slip coefficients, on different types of interface conditions are analyzed while fluid flow and heat transfer in the neighborhood of an interface region are properly characterized. A systematic analysis of the variances among different boundary conditions establishes the convergence or divergence among competing models. It is shown that in general, the variances have a more pronounced effect on the velocity field and a substantially smaller effect on the temperature field and even a smaller effect on the Nusselt number distributions. For heat transfer interface conditions, all four categories generate results, which are quite close to each other for most practical applications. However, small discrepancies could appear for applications dealing with large values of Reynolds number and/or large values of Darcy number. Finally, a set of correlations is given for interchanging the interface velocity and temperature as well as the average Nusselt number among various models.