Trader sentiment for San Francisco’s July 12 high temperature centers on short-range forecast uncertainty around the marine layer depth and afternoon onshore flow strength. Most ensemble guidance shows a persistent cool, moist boundary layer capping daytime highs near 70–75 °F, with the 74–75 °F bracket edging ahead at 26.5 % implied probability because a few models allow modest warming if the inversion lifts earlier. The closely priced 72–73 °F outcome reflects the typical July climatology of 67–71 °F highs when fog lingers into midday. Key variables traders are watching include the 12–18 UTC wind shift at the coast, 850 hPa temperature anomalies, and any thermal-trough development that could briefly suppress the marine push and push readings a degree or two higher before the sea breeze reasserts itself.