The temperature on the outer cladding surface of a light water reactor four-cusp channel has been analytically determined at steady state and with a linear variation of the coolant/cladding heat transfer coefficient along the curvilinear coordinate. The heat balance equation is transformed into a Sturm-Liouville problem and is solved by the Green’s function. The general solution is provided in closed form by using Airy functions of the first and second kinds; hence, the azimuthal temperature distribution is easily amenable to a monodimensional integral of Airy functions. Numerical results are plotted, and the influence of geometric and physical parameters is discussed.