The Mean Layer Temperature – NOAA Climate Data Record (CDR) provides long-term temperature measurements for a thick layer of the upper atmosphere. Input data comes from Mean Layer Temperature (MLT) level-1c swath radiances taken by the Microwave Sounding Unit (MSU), the Advanced Microwave Sounder Unit-A (AMSU-A) and the Advanced Technology Microwave Sounder (ATMS) aboard NOAA, NASA, and EUMETSAT satellites. The CDR was calibrated using the NOAA STAR Integrated Microwave Inter-Calibration Approach (IMICA) to remove calibration drifting errors. The final dataset incorporates inter-satellite bias corrections to ensure consistency, and adjustments that account for diurnal drift effect, differences between viewing angles, and channel frequency differences between sensors. The final record is a monthly global gridded dataset with 2.5°x2.5° Latitude/Longitude resolution, and extends from 1978–present.