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Precipitation
These reports are used to prepare our official forecasts. They are generated using data stored in the CDEC database and are intended for use in water supply forecasting. If you're interested in what's happening right now they probably will be of little interest to you.
Monthly precipitation data is collected from telephone reports from manual observers and is generally completed by the third business day of each month. In most cases, this is at least a week earlier than publication by the National Weather Service.
Advance collection of these data is funded by the State to provide water managers with a timely water supply forecast.
Data published here is provisional. Occasionally, errors are discovered after we review the offical observer sheets.
California Cooperative Snow Surveys