A system and/or method for sensing the presence of moisture (e.g., rain) and/or other material(s) on a window such as a vehicle window (e.g., vehicle windshield or backlite). In certain example embodiments, a capacitor-based system and/or method is provided for auto-correlating sensor data to determine the existence of a material on the window, and then cross-correlating sensor data to identify the type and/or amount of that material (e.g., rain). This data may be used to actuate and/or deactivate a vehicle's wiper(s), and/or adjust wiper speed. In certain example embodiments, the sensor may include an array of at least two capacitors. In certain example embodiments, the system and/or method may perform check(s) to enhance the accuracy of the detection by comparing, for example, the sign of autocorrelation values, maximum autocorrelation values, and/or gradients of autocorrelation values.