Recent National Weather Service and ensemble model guidance points to a San Francisco high temperature on August 5 centered in the low-to-mid 70s, driven by a persistent marine layer and moderate onshore flow that limits inland heating. The 74–75 °F bin leads at 28.5 % because several runs show brief afternoon clearing allowing peaks near 75 °F, while the closely matched 72–73 °F outcome (26.5 %) reflects typical August climatology tempered by coastal upwelling. Key differentiating factors include marine-layer depth, which can suppress temperatures by several degrees if it lingers, and any shift in the thermal trough that could allow brief warming. Updated 00Z and 12Z model cycles plus NWS afternoon briefings will refine these probabilities before market resolution.