An image sensing system for a vehicle includes an imaging sensor and a control. The imaging sensor has a two-dimensional array of light sensing pixels, and has a forward field of view through the windshield of a vehicle equipped with the image sensing system to the exterior of the equipped vehicle. The imaging sensor is operable to capture image data and the control includes an image processor. The image sensing system determines an object of interest present in the forward field of view of the imaging sensor via processing of the captured image data by the image processor. The image processing includes spatial filtering. The spatial filtering may, at least in part, identify atmospheric conditions. The spatial filtering may include analysis of a spectral signature representative of at least one detected light source present in the forward field of view of the imaging sensor.