Skip to main content
U.S. flag

An official website of the United States government

California Precipitation Data (Federated)

Published by California Department of Water Resources | State of California | Catalog Last Checked: October 24, 2026 at 08:44 PM | Dataset Last Updated: September 28, 2026 at 04:43 PM
This federated catalog entry enhances discovery of selected precipitation resources maintained by the California Data Exchange Center (CDEC) by describing and linking to them from the California Natural Resources Agency Open Data Platform. CDEC remains the authoritative source for these resources, and the underlying data, applications, and services continue to be hosted and maintained by CDEC. Data stewardship, quality control, update schedules, and authoritative publication remain with CDEC and the originating data providers. This catalog entry does not replace or replicate CDEC functionality; it provides metadata and links that help users discover and access CDEC resources from a broader statewide data catalog. CDEC provides a centralized system for storing and processing real-time hydrologic information collected by numerous cooperating agencies throughout California, including the National Weather Service, U.S. Bureau of Reclamation, U.S. Army Corps of Engineers, U.S. Geological Survey, and utility operators such as PG&E and SMUD. CDEC precipitation data consists of direct observations from a statewide sensor network — over 140 agencies currently contribute data through more than 1,100 remote stations and roughly 8,500 sensors, transmitted via the state microwave system, GOES satellite, and automated data exchange. Data is publicly accessible at no cost; however, users should be aware that data are provisional and subject to revision. This entry is organized into four groups of resources: composite precipitation indices, regional station groups, discovery and programmatic access tools, and reference and documentation resources. * **Composite Precipitation Indices** — Three primary indices maintained by DWR: the Northern Sierra 8-Station Index (8SI), San Joaquin 5-Station Index (5SI), and Tulare Basin 6-Station Index (6SI). Each is computed as an unweighted arithmetic mean of cumulative water-year-to-date precipitation across its member stations, and is used by DWR in developing water supply forecasts each water year as part of Bulletin 120. Both daily and monthly index values are provided, along with the underlying component-station data for each index (8 stations for 8SI, 5 for 5SI, 6 for 6SI) for users who need station-level detail rather than the composite value alone. * **PG&E and Oroville/Feather River Regional Groups** — Six regional precipitation station groups: five operated by Pacific Gas & Electric (PP1–PP5) and one operated by DWR covering the Oroville/Feather River area (OR1). These groups report a mix of daily and hourly data depending on station, and several groups share member stations with one another (for example, PP3's six stations are entirely a subset of PP1's eleven, and PP2's four stations are entirely a subset of PP4's roster) — see individual resource descriptions for full station lists and overlap details. * **Discovery and Programmatic Access** — Tools for discovering stations not itemized in this entry and for retrieving their data directly. These include a searchable station directory that can be filtered by sensor type, station lists organized geographically by river basin, a general-purpose query builder for retrieving daily or monthly data from individual CDEC stations, and the DWR-maintained Python package cdec_maps for programmatic and automated access to station metadata and time series. * **Reference and Documentation** — Supporting resources for interpreting and contextualizing CDEC precipitation data, including a statewide water-year monthly precipitation reference reports, format, organized by reporting period or water year, quality-controlled human-readable precipitation summaries, and documentation of CDEC data flags used to indicate data quality, status, or other conditions associated with reported observations. **Scope.** This catalog entry provides metadata and links for a selected set of CDEC precipitation resources and is not intended to reproduce the full CDEC precipitation catalog or provide comprehensive statewide precipitation coverage. CDEC’s broader network includes hundreds of additional stations and products across multiple operators and watersheds that are not individually represented here. For the authoritative data, current products, additional stations, interactive plots, and other precipitation resources, users should access CDEC directly at its precipitation website. The source data and additional data and plots can be accessed directly from CDEC's website (https://cdec.water.ca.gov/snow_rain.html).

Resources

23 resources available

  • Quality-Controlled Precipitation Summary (HYD Report)

    HTML
  • CDEC Precipitation Station Search

    HTML
  • CDEC Daily Precipitation Stations (by River Basin)

    HTML
  • CDEC Data Flag Definitions

    HTML
  • CDEC Monthly Precipitation Stations (by River Basin)

    HTML
  • CDEC Water Year Monthly Precipitation, All Stations (PRECIPMON)

    HTML
  • Station Precipitation Query Builder (Any CDEC Station))

    CSV
  • Northern Sierra 8-Station Precipitation Index (8SI) — Daily

    CSV
  • San Joaquin 5-Station Precipitation Index (5SI) — Daily

    CSV
  • Tulare Basin 6-Station Precipitation Index (6SI) — Daily

    CSV
  • OR1: Oroville/Feather River Precipitation

    CSV
  • San Joaquin 5-Station Precipitation Group (5SP) — Component Stations

    CSV
  • Northern Sierra 8-Station Precipitation Group (8SP) — Component Stations

    CSV
  • Tulare Basin 6-Station Precipitation Group (6SP) — Component Stations

    CSV
  • PP4: PG&E Precipitation, Central Hydro 2

    CSV
  • 8SI Monthly

    CSV
  • 5SI Monthly

    CSV
  • 6SI Monthly

    CSV
  • cdec_maps Python Package (Programmatic Station & Data Access)

    SOFT
  • PP1: PG&E Precipitation, Northern Hydro 1

    CSV
  • PP2: PG&E Precipitation, Northern Hydro 2

    CSV
  • PP3: PG&E Precipitation, Central Hydro 1

    CSV
  • PP5: PG&E Precipitation, Southern Hydro

    CSV

Find Related Datasets

data.gov

An official website of the GSA's Technology Transformation Services

Looking for U.S. government information and services?
Visit USA.gov