The limited 2025 salmon fishing season opened in mid-July and continues through October on the Feather, American, and Mokelumne rivers.  Early summer (July-August) conditions were tough for the beginning of the run and early fishing.  The river, Delta, and Bay in August were too warm despite three wet years in a row with above average reservoir storage and below normal summer air temperatures.

The lower Sacramento River was too warm (Figure 1). Flows dropped in mid-August with two-thirds of reservoir releases being diverted before reaching the Delta.  Water temperatures were above the 20ºC standard to protect salmon during their run from the ocean to the rivers.  River flow should be near 10,000 cfs to maintain the water temperature standard.

The Delta was too warm (Figure 2).  Water temperatures in August reached the 22ºC level, considered highly stressful and avoided by salmon, as Delta inflow dropped from 20,000 cfs to 10,000 cfs.  Delta inflow at Freeport should be about 20,000 cfs for good fishing conditions.

The Bay was too warm (Figure 3).  Water temperatures exceeded 22ºC, and dissolved oxygen fell to near the standard of 6 mg/ l.  Delta outflow fell to near 4000 cfs, while south Delta exports exceeded 10,000 cfs.  Delta outflow should be around 10,000 cfs for good fishing conditions.

Figure 1. Lower Sacramento River streamflow and water temperature in July-August 2025. Red line is the water quality standard for water temperature.

Figure 2. Streamflow and water temperature of the Sacramento River at northern entrance to the Delta over the past 30 days.

Figure 3. Water temperature and dissolved oxygen concentration in the east Bay in July-August 2025.