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)
Today: Mostly cloudy in the morning then becoming partly cloudy. Widespread fog early in the morning. Areas of fog late in the morning, then patchy fog early in the afternoon. Highs 51 to 57. Light winds.

Tonight: Mostly clear in the evening then becoming mostly cloudy. Patchy fog after midnight. Lows 36 to 42. Light winds.

Tuesday: Mostly cloudy. Highs around 59. Light winds.

Tuesday Night: Mostly cloudy. A slight chance of rain after midnight. Lows around 44. Light winds.

Wednesday: Mostly cloudy in the morning then becoming partly cloudy. Highs around 60. Northwest winds up to 10 mph.

Wednesday Night: Mostly clear. Lows around 42.

Thursday: Mostly cloudy. Highs around 58.

Thursday Night: Partly cloudy. Lows around 44.

Friday through Sunday: Mostly cloudy. Highs around 61. Lows around 45.
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.