National Weather Service California Nevada River Forecast Center Department of Commerce National Oceanic and Atmospheric Administration National Weather Service

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SAN JOAQUIN RIVER - PATTERSON (PATC1)
Latitude: 37.49º NLongitude: 121.08º WElevation: 97 Feet
Location: Stanislaus County in CaliforniaRiver Group: San Joaquin
Monitor Stage: 48.0 FeetFlood Stage: 54.7 FeetDanger Stage: 55.7 Feet

Observed Data Credit
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Raw streamflow data is provided by the California Department of Water Resources.
View CA DWR Data for this station location.

Historical Stage/Flow Data
Note: Water Year 2025 is currently showing peak daily mean values. These will be updated to instantaneous peaks in the coming months.
Water Year
Peak Discharge (cfs)
Stage (feet)
Date
 Most Recent 5 Years
2025* 3,474 37.43 Mar 23, 2025
2024* 5,740 41.64 Mar 7, 2024
2023* 24,500 52.24 Mar 27, 2023
2022* 1,190 33.41 Dec 31, 2021
2021* 1,770 34.50 Feb 1, 2021
 Historical High Stage/Flow Events (Period of Record - Oct 1969 to Present) - Ranked by Flow
1983* 28,700 51.26 Mar 4, 1983
2006* 27,612 50.97 Apr 10, 2006
2017* 25,600 51.71 Feb 22, 2017
1980* 24,900 50.57 Feb 25, 1980
2023* 24,500 52.24 Mar 27, 2023
1986* 23,000 49.65 Mar 18, 1986
* Discharge affected by regulation or diversion
** Most recent continuous record back to Oct 1969 with segmented periods back to Apr 1938
Location Photographs
ESRI™ Locator Map
Official 7 Day National Weather Service Forecast   (CAZ019)
Tonight: A chance of rain until early morning, then rain late in the night. Lows 35 to 42. Southeast winds 10 to 15 mph with gusts to around 25 mph.

Thursday: Rain in the morning, then a chance of rain in the afternoon. Highs 44 to 52. Southeast winds 10 to 20 mph with gusts to around 30 mph.

Thursday Night: Mostly clear. A slight chance of rain in the evening. Lows 30 to 35. Southwest winds up to 15 mph. Gusts up to 30 mph in the evening.

Friday: Partly cloudy in the morning then becoming mostly cloudy. Highs 46 to 53. Southeast winds up to 10 mph.

Friday Night: Mostly clear. Lows 32 to 38. Southeast winds up to 10 mph.

Saturday: Mostly cloudy. Highs 51 to 56.

Saturday Night: Mostly cloudy with a chance of rain. Lows 43 to 48.

Sunday: Mostly cloudy with a chance of rain. Highs around 59.

Sunday Night through Tuesday Night: Rain likely. Lows 47 to 53. Highs 56 to 65.

Wednesday: Mostly cloudy with a chance of rain. Highs around 58.
Flood Impacts
58.3 FeetStages above 58.3 feet result in flooding outside the levee. Top of levee.
Product Disclaimer

This river graphic is not intended to serve as a substitute for official flood watches, warnings, advisories, or statements issued by the NWS Sacramento Weather Forecast Office. Observations are preliminary and subject to change. River levels identified as "forecast" should be consistent with those contained in official NWS products. River levels identified as "guidance" have significant uncertainty due to future weather or reservoir regulation and are provided for planning purposes only.