CHIRPS3 FAQ

Is there a CHIRPS3 website?

Yes: https://chc.ucsb.edu/data/chirps3

Where can I get CHIRPS3 data?

Via a web browser https://data.chc.ucsb.edu/products/CHIRPS/v3.0/. The Climate Hazards Center landing page for all our public data is https://data.chc.ucsb.edu

Do rainfall amounts differ in CHIRPS3 and CHIRPS2?

Yes. Rainfall amounts differ between CHIRPS2 and CHIRPS3 primarily because of two important improvements in CHIRPS3.

• First, the satellite-only CHIRP3 has higher precipitation variance than CHIRP2, improving the representation of both wet and dry extremes. CHIRP2 tended to underestimate precipitation variance, including extreme rainfall amounts and rainfall deficits.
• Second, the station observations used in CHIRPS3 are gauge-undercatch corrected. Rain gauges can systematically underestimate precipitation, particularly under windy conditions and in complex terrain. Applying this correction generally makes CHIRPS3 wetter than CHIRPS2

What is the spatial resolution of CHIRPS3?

• Chirps is produced at 0.05 x 0.05 degree spatial resolution.
• For daily Africa data we also provide a 0.25 x 0.25 degree spatial resolution product.

What are the spatial domain available for CHIRPS3?

• Global 60N-60S, 180W-180E @0.05 deg resolution = maps 7200 x 2400 pixels
• Africa 40N-40S, 20W-55E @0.05 deg resolution = maps 1500 x 1600 pixels
• Latin America 35N-60N, 120W-34W @0.05 deg resolution = maps 1720 x 1900 pixels

What are the file formats available for CHIRPS3?

• .tif
• .bil
• .netcdf
• .cog

What are the time steps available for CHIRPS3?

• pentad
• dekad
• daily
• monthly
• 2-monthly
• 3-monthly
• annual

How does CHIRPS3 define a pentad?

• 6 pentads = 1 calendar month. Each of first 5 pentads in a month have 5 days. The last pentad contains all the days from the 26th to the end of the month.

How does CHIRPS3 define a dekad?

• A dekad = sum of 2 pentads. There are 3 dekads in a calendar month.

How are CHIRPS3 daily data produced?

• CHIRPS3 is fundamentally calculated at pentadal and monthly scales; daily values are produced by disaggregating pentadal totals using either IMERG Late or ERA5.

Why are there two versions of CHIRPS3 daily data?

CHIRPS3 Final provides an IMERG-based daily product and an ERA5-based daily product. The IMERG-based archive begins in 2001, whereas the ERA5-based daily product extends back to 1981. Prelim provides only the IMERG-based daily disaggregation.

What units is CHIRPS in?

Total mm for given time step, mm/pentad, mm/month, etc.

What value is used for Bad Values?

-9999.

What is the latency of the CHIRPS product?

• The preliminary CHIRPS v3.0 uses readily available in situ station observations, including reports from the World Meteorological Organization (WMO) Global Telecommunications System (GTS), NOAA’s Global Historical Climatology Network (GHCN), Synoptic Summary of the Day (SSOD), and from Mexico’s National Water Commission (CONAGUA). Additional data sources include: Instituto de Hidrología, Meteorología y Estudios Ambientales (IDEAM, Colombia’s Institute of Hydrology, Meteorology and Environmental Studies), Instituto Meteorológico Nacional de Costa Rica (IMN, Costa Rica’s National Meteorological Agency), Republic of Korea Meteorological Administration, Drought Information System for Southern South America (SISSA), Instituto Nacional de Sismología, Vulcanologia, Meteorologia e Hidrología (INSIVUMEH, Guatemala’s National Institute for Seismology, Vulcanology, Meteorology and Hydrology), Dirección Meteorológica de Chile (Chilean Meteorological Service), Deutscher Wetterdienst (DWD, German Meteorological Service), 3D-Printed Automatic Weather Stations (3D-PAWS) in Kenya.
• Final CHIRPS (all station data) is available sometime in the third week of the following month.

What is the temporal range for CHIRPS?

CHIRPS is available from 1981 to near-real time.

What is the spatial density of station data used in CHIRPS?

The number and spatial distribution of rain gauges incorporated into CHIRPS3 vary by location and over time. Some regions have relatively dense station coverage, while others are more station-sparse, and the number of available stations can change substantially from month to month and year to year.

• CHC provides several diagnostic products that allow users to examine station coverage. Monthly Station Density maps show the number of stations within each grid cell at both 0.05° and 0.25° resolutions, helping users identify station-dense and station-sparse regions. Station Density maps are also produced for CHIRPS preliminary and final pentads. Additional information on the station inputs used in CHIRPS3 is available through the CHIRPS3 Diagnostics products.

• Station observations can also be explored through the Early Warning eXplorer (EWX) using the RCHECKS layer. These “reality checks” display station observations over the CHIRPS3 rainfall field, allowing users to examine how station availability and agreement with the CHIRP3 satellite rainfall estimates vary across space and time.

You can access EWX here.

• On the left open up the Global or Africa tab.
• Then double click on RCHECKS
• You will have to zoom in to see squares with black dots in the middle.
  • These are 10x10 pixel boxes of the station value on top of the CHIRPS3 field, a "reality check" to see if the stations match the background field.
  • You can zoom in on a location, then cycle through month/years to see how the number of stations changes with time. It is pretty significant in some areas.

How was CHIRPS funded?

CHIRPS has been supported by funding from:

• the U.S. Agency for International Development (USAID)
• the Famine Early Warning Systems Network (FEWS NET)
• the National Aeronautics and Space Administration (NASA) and
• the National Oceanic and Atmospheric Administration (NOAA)

How good is CHIRPS?

For its intended uses, Seasonal Drought monitoring and Trend Analysis, it is very good; see [1]

How do I reference CHIRPS3 in publications?

Funk, C., Peterson, P., Harrison, L. et al. The Climate Hazards Center Infrared Precipitation with Stations, Version 3. Sci Data 13, 718 (2026). https://doi.org/10.1038/s41597-026-07096-4

What are some of the changes in version 3.0?

• Since v1.8 we have added many new stations around the world. In particular, 400 in Peru, 1,200 across Africa from Sharon Nicholson, 11,000 in Brazil, over 1,000 in Mexico (Conagua), 76 from Southern Africa, 500 in Russia, 250 in Central Asia and 400 across Central America. In addition we have topped off data from several African countries. The Conagua stations are available in near-real time and will directly improve our preliminary CHIRPS product.
• Daily data now available for the Globe
• NetCDF format added
• Replaced erroneous stations in Tanzania
• Expanded diagnostics, stations by Country plots, EWX rchecks, station comparison/*badness* plots, station density maps, pentad and monthly png's of excluded stations,

Is there a copy of the paper online?

Yes.

• CHC Publications
• USGS website

Who do I contact with CHIRPS questions?

Help chc-help@geog.ucsb.edu

Pete Peterson pete@geog.ucsb.edu

Robert Saldivar rsaldivar.ucsb.edu