Simultaneous quantitative measurements are made of both the temperature and velocity fields for two-dimensional transient natural convection in an inclined rectangular enclosure using calibrated multichannel electronic interferometry and digital particle image velocimetry. The transient boundary conditions are initiated impulsively by heating and cooling two opposing walls. The evolution of the flow to steady-state is determined for a Prandtl number of 6.38, a Rayleigh number of 1.5 x 10(5) and an aspect ratio of 1.0, at angles of inclination of pi/4, pi/2 and 3 pi/4.