Climate Data

GPCP (Monthly): Global Precipitation Climatology Project

Data from rain gauge stations, satellites, and sounding observations have been merged to estimate monthly rainfall on a 2.5-degree global grid from 1979 to the present. The careful combination of satellite-based rainfall estimates provides the most complete analysis of rainfall available to date over the global oceans, and adds necessary spatial detail to the rainfall analyses over land. In addition to the combination of these data sets, estimates of the uncertainties in the rainfall analysis are provided as a part of the GPCP products. The August 2012 GPCP v2.2 uses upgraded emission and scattering algorithms, the GPCC precipitation gauge analysis, and inclusion of the DMSP F17 SSMIS. The December 2012 update contains "recomputed" October 2012 values.

Key Strengths:

  • The monthly data sets is considered the standard for global precipitation. Often used in model evaluation.
  • Provides estimates of uncertainty. Constantly improving.

Key Limitations:

  • Grid resolution is 'only' 2.5x2.5
  • Over the oceans where satellite data are used, estimates may be biased low at low precipitation rates.

Years of Record

1979/01 to 2013/08



Climatology | Monthly

Data Time Period Extended?

yes, data set is extended


Spatial Resolution

2.5 x 2.5 (monthly)

Ocean or Land


Missing Data Flag

spatially complete

Vertical Levels

Input Data

rain gauge stations, satellites, and sounding observations

Earth system components and main variables

Key Figures

Click the thumbnails to view larger sizes



Climate Data Guide Image: GPCP annual mean climatology Climatological annual mean precipitation (mm/day) for 1979-2010. The areal mean for the entire grid is 2.67 mm/day. (Climate Data Guide; D. Shea)
Climate Data Guide Image: GPCP Top: Areal weighted mean of precipitation rate for 1979-2010. Bottom: zonal mean precipitation (mm/day). The thin horizontal line is the climatological long term mean. (Climate Data Guide; D. Shea)

Cite this page

National Center for Atmospheric Research Staff (Eds). Last modified 03 Jan 2014. "The Climate Data Guide: GPCP (Monthly): Global Precipitation Climatology Project." Retrieved from

Acknowledgement of any material taken from this page is appreciated. On behalf of experts who have contributed data, advice, and/or figures, please cite their work as well.