The Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the Suomi National Polar Partnership (S-NPP) and the Joint Polar Satellite System (JPSS) builds upon heritage sensors, Advanced Very High Resolution Radiometer (AVHRR) and Moderate-Resolution Imaging Spectroradiometer (MODIS). The evaluation of AVHRR, MODIS and VIIRS radiometric stability and consistency is needed to ensure continuity of derived data products, including Sea Surface Temperatures (SST). Monitoring of IR Clear-Sky Radiances over Oceans for SST (MICROS; www.star.nesdis.noaa.gov/sod/sst/micros) near-real time web-based system was developed at NESDIS, to monitor model minus observation (M-O) biases in clear-sky ocean brightness temperatures (BT). Double differences (DD) were also employed to evaluate various sensors for consistency. Initially implemented in July 2008 with data from several AVHRRs onboard NOAA-16, -17, -18, -19 and Metop-A, it was extended in January 2012 to include AVHRR-like bands 3.7, 11, and 12μm from Terra and Aqua MODIS, and S-NPP VIIRS. This paper discusses initial results of AVHRR-MODIS-VIIRS cross-platform consistency using MICROS DDs. Work is underway to understand and minimize the observed differences, through collaboration with Sensor Calibration and Community Radiative Transfer Model (CRTM) Teams.