This paper presents an experimental investigation for horizontal solar still that coupled with an induced atmospheric air to evaluate the effect of movable flat external reflector extending and hinged at the side of the still on the performance enhancement in September, October and November at 33.3°N latitude. The average daily yield of the still is examined, namely still without reflector, still with external reflector inclined at 0° (vertical), 10° and 20° respectively. We found that the daily amount of distillate of the solar still with an induced atmospheric air is thoroughly improved using the external reflector. An increase in the distillate productivity by about 23%, 35% and 45% greater than that without external reflector in the middle of September and by about 18%, 39% and 28% in the middle of November is obtained for still with external reflector tilted at 0°, 10°, and 20° respectively. Also, the inclination angle of the external reflector should be adjusted according to month at any latitude, to obtain the optimum potable water productivity.