A flowmeter determines the flow direction of a fluid. The flowmeter has a measuring element, around which the fluid flows. The measuring element has fiber-optic cable and at least two electrical heating elements that lie adjacent to the fiber-optic cable(s) by which a respective heat stream emanating from the respective heating element and directed towards the fiber-optic cable, the directions of the heat streams being at least proportionately reversed. In addition, depending on the flow direction of the fluid, the individual heat streams are correlated to different extents with the flow direction. An electromagnetic wave that can be coupled into the fiber-optic cable(s) can also be influenced according to the temperature of the fiber-optic cable(s). Additionally, the flowmeter has a control unit, which is used to feed electric energy to the two or more heating elements, one after the other, and an evaluation unit, which is used to evaluate the temperature effect of the electromagnetic wave emanating from the individual heat streams and to determine the flow direction of the fluid.