Abstract: An advance in-flight windshear detection system which utilizes a scanning mirror to direct infrared energy located in a three dimensional space in front of the aircraft which is divided into a plurality of variable columns, onto a linear array of photoconductive infrared detectors, the detector emitting a signal representative of the radiant energy at various points in said variable located columns, and a computer for generating a displayable representation of the air temperature in front of the aircraft, the computer further capable of interpolating and extrapolating the air temperatures in the three dimensional space based upon the known and or calculated lapse rate; and a display device for graphically displaying the air temperature in front of the aircraft and above the flight path vector so as to provide a more accurate indication of windshear which is less affected by the uncertainties arising from measuring air temperature in a typically more turbulent region along the flight path vector as the aircraf