A simple hot wire anemometer is described which is made from a combination of straight platinum wires for the measurement of wind direction. The instrument is based on a particular combination of straight platinum wires and a `quadrant sensing' element consisting of a thin mica sheet supplied with a grid of platinum wires on either side, and has conventional electronic circuitry; the output voltage is proportional to V cos φ, where V is the wind speed and φ the wind direction. By using three sets of sensing elements orthogonally oriented in space, the three orthogonal components of wind velocity are obtained directly in the form of three analogue voltages.