map n. A representation, usually on a plane surface, of a region of the earth or heavens.

weather map n. A map or chart showing weather conditions over a wide area at a particular time, compiled from simultaneous observations at different places. (not good enough)

weather map n. Any graphical means of displaying the distribution of meteorological data over a given (usually extensive) area of the earth's surface at a given elevation (or pressure) for plan view maps. (better)