A detailed experimental examination of the dc critical supercurrent densityjcand the microwave (nonzero voltage) supercurrentj&mgr;has been made in proximity effect thin‐film weak links at temperatures above the transition temperature of the link material. These results were correlated with measured dimensional and superconducting parameters of the thin films and the link via a Ginzberg‐Landau (GL) formalism. In the steady state,jcwas found to be adequately described by a one‐dimensional GL formalism similar to that of Likharev and Yakobson but with De Gennes boundary conditions on the order parameter applied at each interface. However,j&mgr;decreases exponentially with increasing voltage and can be interpreted in terms of an interference modulation of the induced pair density within the line at the Josephson frequency.