A MEMS hot wire anemometer consisting of thermoresistive elements arranged in a differential bridge configuration is presented. The arrangement of the elements allows for dedicated heating elements to be omitted from the device without compromising operation or accuracy. Overall power consumption gives velocity and the temperature differential of each element pair is used for direction and has demonstrated a sensing resolution better than 1% and a repeatable accuracy better than 2%. Field trials have demonstrated a robust design with exposure to rain, dust and debris for a period in excess of 12 months with continuing operation.