A nozzle with aperture adjusted automatically in response to an independent variable. Nozzle is defined as a protruding part, conduit, valve, vent, vane, funnel, flap, or diaphragm, connected to a tube, pump, canister or source of fluid, which is any liquid, gas or flowing mixture, for the purpose of controlling the rate of flow, direction, pattern, composition or other features of the flow or mixture. The nozzle of this invention comprises an adjustable aperture and the apparatus of this invention is comprised of the nozzle and the circuitry or processor to receive a signal from at least one sensor and automatically adjust the aperture in response to the signal. The invention can be used with any variety of fluids that are liquid, gas, flowing semi-solid or combination. A preferred embodiment employs the signal from a water vapor pressure sensor to adjust the aperture of the nozzle to disperse a droplet size that creates drizzle.