Abstract: A wind indicator includes a diaphragm which defines a wind passage, the diaphragm is responsive to wind pressure to vary the effective size of the wind passage depending on the velocity of the wind, and vane means are connected to the diaphragm in a position to receive wind passing through the wind passage and responsive to wind direction to maintain the wind passage facing windward; the indicator will show the direction of the wind at very low wind velocity as well as at high wind velocity and is especially useful in areas likely to be invaded by toxic gas.