On this page: Temporal Coverage | Spatial Coverage | Levels | Update Schedule | Download/Plot Data | Analysis Tools
Restrictions | Details | Caveats | File Naming | Citation | References | Original Source | Contact

NOAA CPC (Climate Prediction Center) .25x.25 Daily US UNIFIED Precipitation

Brief Description:

  • High resolution gridded precipitation over the US (from station data) for 1948 to 2006 extending to the present for a real-time version. More Details...

Temporal Coverage:

  • Daily 1948/01/01 to 2006/12/31: measurement accumulated to 12z of the day
  • Daily RT 2007/01/01 to 2014/09/29 .
  • Monthly 1948/01 to 1998/01.

Spatial Coverage:

  • 0.25 - degree latitude x 0.25 - degree longitude US grid (300x120).
  • 20.0N - 50.0N, 230.0E - 305.0E.


  • N/A

Update Schedule:

  • Daily

Download/Plot Data:

Variable Statistic Level Download File Create Plot/Subset
Precipitation Daily Total Surface See List plot
' ' Monthly Total Surface precip.V1.0.mon.mean.nc plot
Precipitation Daily Long Term Mean Surface precip.V1.0.day.ltm.nc plot
' ' Monthly Long Term Mean Surface precip.V1.0.mon.ltm.nc plot
Land-Sea Mask time-invariant Surface lsmask.nc plot

Usage Restrictions:

  • None

Detailed Description:

  • Dataset is derived from 3 sources: NOAA's National Climate Data Center (NCDC) daily co-op stations (1948-...), CPC dataset (River Forecast Centers data + 1st order stations - 1992-...), and daily accumulations from hourly precipitation dataset (1948-...). There are about 13000 station reports each day for 1992-..., and about 8000 reports before that yielding about 3x the reports of any existing historic and operational analyses as of 2000. Future versions of the unified will also include any other raingauge precip datasets. The data were QC-ed to eliminate duplicates and overlapping stations, and standard deviation and buddy checks were applied.. Then they were gridded into 0.25x 0.25, 140W-60W, 20N-60N using a Cressman Scheme.

    Landmask is such that actual data resides between 20N-49.5N (lat grids 1-118) and 233.75E to 292.75 (lon grids 56-292). The PSD files are stored using the landmask to mask out areas that aren't land

    Values are for over the continental US. Data is daily from 1948-2006. Values are accumulated from 12z of the day before to 12z of the day (with no missing grids ).A land-sea mask is supplied.

  • Real Time data is available for 2007 to present. The is not produced exactly the same way as the data before 1999.


  • None

Related File Naming & Structure Information:

File Names:

  • precip.V1.0.yyyy.nc for daily  (In directory: /Datasets/cpc_us_precip/)Note file name change
  • 2007+ in directory: /Datasets/cpc_us_precip/RT/)
  • precip.time,statistic.nc for monthly, long term means  (In directory: /Datasets/cpc_us_precip/)

OpenDap File Names:

  • http://www.esrl.noaa.gov/psd/thredds/dodsC/Datasets/cpc_us_precip/precip.V1.0.yyyy.nc for daily  

Dataset Format and Size:

  • PSD standard NetCDF 37 Mbyte file for each yearly file (packed).
  • PSD standard NetCDF 37 Mbyte file for each daily long term mean file (packed).
  • PSD standard NetCDF 62 Mbyte file for each monthly file (packed).
  • PSD standard NetCDF 1 Mbyte file for each monthly long term mean file (packed).

Missing Data:

  • No missing data.


  • Please note: If you acquire CPC US Unified Precipitation data products from PSD, we ask that you acknowledge us in your use of the data. This may be done by including text such as CPC US Unified Precipitation data provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, USA, from their Web site at http://www.esrl.noaa.gov/psd/ in any documents or publications using these data. We would also appreciate receiving a copy of the relevant publications. This will help PSD to justify keeping the CPC US Unified Precipitation data set freely available online in the future. Thank you!


  • Higgins, et al., R. W., 2000: Improved US Precipitation Quality Control System and Analysis. NCEP/Climate Prediction Center ATLAS No. 6 (in preparation
  • Dataset atlas is available online.
  • Higgins, R. W., J. E. Janowiak, and Y.-P. Yao, 1996: A gridded hourly precipitation data base for the United States (1963-1993). NCEP/Climate Prediction Center Atlas 1, national Centers for Environmental Prediction, 46pp.

Original Source:


  • Physical Sciences Division: Data Management
    325 Broadway
    Boulder, CO 80305-3328