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NOTICE: There is currently a delay in updating the data for the Global Hourly and Daily Summary data. We are working to resolve the issue.

Merged Land–Ocean Surface Temperature Analysis

The Merged Land–Ocean Surface Temperature Analysis (MLOST) is a spatially gridded (5º x 5º) global surface temperature dataset, with monthly resolution from January 1880 to present. NCEI combines a global sea surface (water) temperature (SST) dataset with a global land surface air temperature dataset into this merged dataset of both the Earth’s land and ocean surface temperatures. The SST dataset is the Extended Reconstructed Sea Surface Temperature (ERSST) version 3b. The land surface air temperature dataset is similar to ERSST, but uses data from the Global Historical Climatology Network Monthly (GHCNM) database.

NCEI provides the MLOST dataset as temperature anomalies, relative to a 1971–2000 monthly climatology, following the World Meteorological Organization convention. The MLOST anomalies and error fields are available from NCEI’s FTP area and Climate Monitoring group.

Background Information

Improvements to NOAA's Historical Merged Land–Ocean Surface Temperature Analysis (1880–2006), a peer-reviewed paper, describes the MLOST version 3 processing. It also describes changes between versions 2 and 3. The current version (MLOST v3.5) uses ERSST v3b, which includes only in situ SST data, for historical consistency. Version 3 included both in situ and satellite SST data from ERSST v3. Data for the previous month are now available on the third day of the current month.

Data Access


  • Smith, T.M., R.W. Reynolds, T.C. Peterson, and J. Lawrimore, 2008: Improvements to NOAA's Historical Merged Land–Ocean Surface Temperatures Analysis (1880–2006); Journal of Climate, 21, 2283–2296, doi:
  • Vose, R.S., D. Arndt, V.F. Banzon, D.R. Easterling, B. Gleason, B. Huang, E. Kearns, J.H. Lawrimore, M.J. Menne, T.C. Peterson, R.W. Reynolds, T.M. Smith, C.N. Williams, Jr., and D.L. Wuertz, 2012: NOAA's merged land-ocean surface temperature analysis. Bulletin of the American Meteorological Society, 93, 1677–1685, doi:10.1175/BAMS-D-11-00241.1.

Contact Information

Huai-Min Zhang

Boyin Huang

Tom Smith

Ron Ray