Trader consensus around 68–71°F for San Francisco’s August 17 high reflects National Weather Service and ensemble model guidance showing daytime maxima near or slightly above the 67°F August average. Persistent onshore flow and a shallow marine layer are expected to limit warming despite seasonal solar input, while any thinning of low clouds or reduced wind speeds could allow brief spikes toward 70–71°F. These closely matched outcomes capture model spread in boundary-layer moisture and coastal stratus timing, with historical analogs from similar late-summer patterns confirming that small shifts in the 925 hPa flow or inversion strength commonly separate 68–69°F from 70–71°F realizations. Updated model runs and morning observations will further refine the final range.