We extend Nusselt＇s theory of condensation accounting for subcooling of condensate at a variable wall temperature. Neglecting vapour shear, we derive an equation for heat transfer of a saturated pure vapour condensing on a surface of arbitrary shape. Using this equation, we examine the interaction between heat transfer and nonisothermality specifying the conditions that give the mean beat transfer coefficient independent of the temperature profiles. Applying these conditions to the condensation on a horizontal circular tube and on a sphere, we analytically confirm some numerical results from the literature.