1. A method for determining a visual range in daytime fog, comprising: reading in coordinates of at least one characteristic point of a brightness curve of a camera image of the fog, the brightness curve representing brightness values of image points of the camera image along a reference axis of the camera image; and ascertaining a meteorological visual range in the camera image using the coordinates, a meteorological contrast threshold, and a processing specification, in order to estimate the visual range in fog, the processing specification being designed to model the brightness curve in accordance with at least one of location-dependent scattered light and direction-dependent scattered light through the fog in the camera image.