Monthly grids are available (L3). See readme_OLR.txt and IASI_Flux_and_Temperature.pdf (Data Manager Plan OPIDoR).
Metop-A data are available from January 2008 til October 2021.
Metop-B data are available from April 2013 til September 2022.
Metop-C data are available from July 2019 til September 2022.