California Precipitation Data (Federated)
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).
Data files
| Data title and description | Access data | File details | Last updated |
|---|---|---|---|
Northern Sierra 8-Station Precipitation Index (8SI) — Daily Daily incremental precipitation (sensor 45, inches) for the Northern Sierra 8-Station Precipitation Index — a pre-computed composite value, not the individual readings of the eight member stations that feed into it. Used by DWR in water supply forecasting (Bulletin 120). Confirmed data availability begins Water Year 2016 (October 1, 2015); dates prior to this return placeholder values ("---") indicating no recorded observations. Data flagged "e" indicates an estimated (not final) value, subject to revision during CDEC's standard quality-control process. | Download | CSV | 09/29/26 |
San Joaquin 5-Station Precipitation Index (5SI) — Daily Daily incremental precipitation (sensor 45, inches) for the San Joaquin 5-Station Precipitation Index — a pre-computed composite value, not the individual readings of the five member stations that feed into it. Data availability begins Water Year 2016 (October 1, 2015). | Download | CSV | 09/29/26 |
Tulare Basin 6-Station Precipitation Index (6SI) — Daily Daily incremental precipitation (sensor 45, inches) for the Tulare Basin 6-Station Precipitation Index — a pre-computed composite value, not the individual readings of the six member stations that feed into it. Data availability begins Water Year 2016 (October 1, 2015). | Download | CSV | 09/29/26 |
8SI Monthly Monthly accumulated precipitation (sensor 2, inches) for the Northern Sierra 8-Station Precipitation Index. | Download | CSV | 09/29/26 |
5SI Monthly Monthly accumulated precipitation (sensor 2, inches) for the San Joaquin 5-Station Precipitation Index. | Download | CSV | 09/29/26 |
6SI Monthly Monthly accumulated precipitation (sensor 2, inches) for the Tulare Basin 6-Station Precipitation Index. | Download | CSV | 09/29/26 |
Northern Sierra 8-Station Precipitation Group (8SP) — Component Stations Daily precipitation readings for the individual component stations feeding into 8SI: Mount Shasta City (MTS), Shasta Dam (SHS/SHA — two co-located sensors under separate station codes), Mineral (MIN), Brush Creek RS (BRS), Quincy (QCY), Sierraville RS (SVL), Pacific House (PFH), and Blue Canyon (BLC). Most stations report via two sensor types: sensor 45 (PPT INC) and sensor 203 (PPTINC4), representing two independently operated rain gauge instruments. Unlike the composite 8SI resource, this provides underlying raw station-level readings. | Download | CSV | 09/29/26 |
San Joaquin 5-Station Precipitation Group (5SP) — Component Stations Daily precipitation readings for stations in the San Joaquin 5-Station Precipitation Group. Note: this group includes seven stations — CVS, HTH, BAL, NFR, and CRR are the five official members of the 5SI index calculation; __MIL and HNT are additional stations included in the group whose role in the index formula has not been confirmed (inquiry sent to CDEC, response pending).__Sensor coverage (45/203) varies by station. | Download | CSV | 09/29/26 |
Tulare Basin 6-Station Precipitation Group (6SP) — Component Stations Daily precipitation readings for the six official component stations of the Tulare Basin 6-Station Index: TSH, BAL, GNF, ISB, PSC, SGV. Note: BAL also appears as a member of the San Joaquin 5-Station Group (5SP). All six stations report via sensor 203 (PPTINC4) only. | Download | CSV | 09/29/26 |
PP1: PG&E Precipitation, Northern Hydro 1 Precipitation data for 11 PG&E-operated stations in the Northern Hydro 1 region: LSP, HTC, BRE, DPH, PR1, PR3, DRC, PR5, HLH, FBS, MCL. Most stations report both daily (sensor 45, PPT INC) and hourly (sensor 16, RAINTIP) data; HLH reports hourly via sensor 2 (RAIN) instead. Sensor 45 period of record begins 07/02/1996 (station HTC, servlet-verified). ⚠️ Due to data volume (hourly records across 11 stations spanning ~30 years), this resource is not suitable for automatic ingestion. The linked URL returns one representative year (2024) as a preview. To retrieve other date ranges, modify the Start and End parameters directly in the URL (format: YYYY-MM-DD), and query in yearly or shorter increments. Note: PP1 fully contains all 6 stations in the PP3 group (LSP, BRE, DPH, DRC, HLH, FBS) — PP3 does not add any unique stations beyond what PP1 already provides. | Download | CSV | 09/29/26 |
PP2: PG&E Precipitation, Northern Hydro 2 Precipitation data for 4 PG&E-operated stations: PVL, CBO, BUP, FBS. CBO and FBS report hourly only (sensor 16, RAINTIP), with no daily-duration alternative. PVL and BUP report both daily (sensor 45) and hourly. Sensor 45 period of record begins approximately 09/1996–1998 depending on station. ⚠️ Due to data volume, this resource is not suitable for automatic ingestion. The linked URL returns one representative year (2024) as a preview. Modify the Start/End parameters to query other date ranges (yearly or shorter increments recommended). Note: all 4 stations in this group also appear in PP4; PP2 does not add unique stations beyond PP4's roster. FBS also appears in PP1/PP3. Format: CSV (query template — not suitable for direct CKAN ingestion) | Download | CSV | 09/29/26 |
PP3: PG&E Precipitation, Central Hydro 1 Precipitation data for 6 PG&E-operated stations: LSP, BRE, DPH, DRC, HLH, FBS. HLH reports hourly via sensor 2 (RAIN); all others via sensor 16 (RAINTIP). DRC has notable data gaps in both daily and hourly readings. ⚠️ Due to data volume, this resource is not suitable for automatic ingestion. The linked URL returns one representative year (2024) as a preview. Modify the Start/End parameters to query other date ranges (yearly or shorter increments recommended). Note: all 6 stations in this group are also members of the larger PP1 group — PP3 does not add any stations beyond what PP1 already provides. Format: CSV (query template — not suitable for direct CKAN ingestion) | Download | CSV | 09/29/26 |
PP4: PG&E Precipitation, Central Hydro 2 Description: Precipitation data for 9 PG&E-operated stations: SSR, PVL, CBO, TCP, BUP, PCR, FBS, SFB, SPW. PCR, SFB, and SPW report hourly via sensor 2 (RAIN); others via sensor 16 (RAINTIP). CBO and FBS report hourly only. ⚠️ Due to data volume, this resource is not suitable for automatic ingestion. The linked URL returns one representative year (2024) as a preview. Modify the Start/End parameters to query other date ranges (yearly or shorter increments recommended). Note: PVL, CBO, BUP, and FBS are shared with PP2 (which does not add unique stations beyond this group); FBS is also shared with PP1/PP3. Format: CSV (query template — not suitable for direct CKAN ingestion) | Download | CSV | 09/29/26 |
PP5: PG&E Precipitation, Southern Hydro Precipitation data for 7 PG&E-operated stations: MBR, WSD, BAL, AGW, CRR, SGV, KPH. Mixed daily (sensor 45) and hourly (sensor 16) reporting across stations. Sensor 45 period of record begins 10/01/1998/ ⚠️ Due to data volume, this resource is not suitable for automatic ingestion. The linked URL returns one representative year (2024) as a preview. Modify the Start/End parameters to query other date ranges (yearly or shorter increments recommended). Note: BAL is also a member of the San Joaquin 5-Station Group (5SP) and Tulare Basin 6-Station Group (6SP). Format: CSV (query template — not suitable for direct CKAN ingestion) | Download | CSV | 09/29/26 |
OR1: Oroville/Feather River Precipitation Daily precipitation data (sensor 45, PPT INC) for 8 DWR-operated stations: ORO, SBY, BRS, SVL, QCY, CAM, DES, CNY. Sensor 45 period of record begins 01/01/1987 (station ORO -- earlier than PG&E-operated groups). Note: BRS, SVL, and QCY are also members of the Northern Sierra 8-Station Group (8SP). | Download | CSV | 09/29/26 |
Station Precipitation Query Builder (Any CDEC Station)) CDEC's official query builder for retrieving CSV data from any individual station, or multiple stations at once by entering comma-separated three-letter station codes. Users select station(s), sensor, duration, and date range via the form, and the tool generates the appropriate CSV download. Example query generated by this tool — single station, daily, sensor 2: https://cdec.water.ca.gov/dynamicapp/req/CSVDataServlet?Stations=ORO&SensorNums=2&dur_code=D&Start=2015-01-01&End=2024-12-31 Multiple stations (comma-separated): https://cdec.water.ca.gov/dynamicapp/req/CSVDataServlet?Stations=ORO,HTC,BLC&SensorNums=2&dur_code=D&Start=2015-01-01&End=2024-12-31 Note: monthly-duration queries (dur_code=M) for sensor 2 are only available for stations that CDEC classifies as monthly-reporting stations (see the [Monthly Precipitation Stations by River Basin list](https://cdec.water.ca.gov/reportapp/javareports?name=MonthlyPrecip)) — daily-only stations do not support monthly-duration queries. Additionally, monthly reporting start dates vary significantly by station (as early as the 1980s for some stations, as recent as January 2025 for others) — if a monthly query returns no data, try a more recent date range before concluding the station does not support monthly reporting. Station codes can be found via the [CDEC Precipitation Station Search](https://cdec.water.ca.gov/dynamicapp/staSearch?sta=&sensor_chk=on&sensor=45&collect=DATA+COLLECTION+TYPE&dur=D), the [Daily](https://cdec.water.ca.gov/reportapp/javareports?name=DailyPrecip) and [Monthly](https://cdec.water.ca.gov/reportapp/javareports?name=MonthlyPrecip) Precipitation Stations by River Basin lists, or the [PRECIPMON reference report](https://cdec.water.ca.gov/reportapp/javareports?name=PRECIPMON). | Download | CSV | 09/29/26 |
Supporting files
| Data title and description | Access data | File details | Last updated |
|---|---|---|---|
CDEC Precipitation Station Search https://cdec.water.ca.gov/dynamicapp/staSearch?sta=&sensor_chk=on&sensor=45&collect=DATA+COLLECTION+TYPE&dur=D Searchable table of 613 CDEC stations reporting daily incremental precipitation, including name, river basin, county, coordinates, elevation, and operator. Includes built-in Copy/Excel/CSV/PDF/Print export buttons (client-side only — no static download URL exists). | Download | HTML | 09/29/26 |
cdec_maps Python Package (Programmatic Station & Data Access) Open-source package providing read_all_stations() for bulk station metadata and read_station_data() for time-series retrieval. Provides path for programmatic/automated access. | Download | SOFTWARE (PYTHON PACKAGE) | 09/29/26 |
CDEC Monthly Precipitation Stations (by River Basin) Directory of CDEC stations reporting monthly precipitation, organized geographically by river basin from north to south. Includes station name, ID, elevation, coordinates, county, and operating agency for each station. Regenerated live on each page load (not a static historical file). A companion report for daily-reporting stations is available at https://cdec.water.ca.gov/reportapp/javareports?name=DailyPrecip. | Download | HTML | 09/29/26 |
CDEC Daily Precipitation Stations (by River Basin) Directory of CDEC stations reporting daily precipitation, organized geographically by river basin from north to south. Includes station name, ID, elevation, coordinates, county, and operating agency. Station metadata only — no precipitation values included. Regenerated live on each page load. Station set differs from the CDEC Precipitation Station Search (Resource 16), which is filtered by sensor rather than organized by basin. | Download | HTML | 09/29/26 |
CDEC Water Year Monthly Precipitation, All Stations (PRECIPMON) Water-year monthly precipitation totals for all CDEC precipitation stations statewide, ordered by station name — useful as a discovery tool to identify which stations report monthly precipitation. No separate machine-readable export was identified for this specific report. To retrieve the underlying data programmatically for any station listed here, use the [Station Monthly Precipitation Query Template](https://data.cnra.ca.gov/dataset/california-precipitation-data-federated/resource/bef4fb78-d5b1-4475-b860-6b689f5b9790), substituting the desired station code into the Stations parameter. | Download | HTML | 09/29/26 |
Quality-Controlled Precipitation Summary (HYD Report) Human-readable precipitation summary showing quality-controlled station precipitation accumulations, including station identifiers, station names, elevations, and recent 6-hour and 24-hour precipitation totals. The report is generated by the National Weather Service California-Nevada River Forecast Center and made available through CDEC. | Download | HTML | 09/29/26 |
CDEC Data Flag Definitions Includes information about commonly used data flag. | Download | HTML | 09/29/26 |