Marine layer depth near 1,000 feet and persistent onshore flow from the Pacific are the dominant factors anchoring trader consensus around a 72–73°F high for San Francisco on August 6. This shallow, cool, moist boundary layer—common in late summer—limits daytime warming along the immediate coast even as high pressure builds inland. Official guidance from NWS Bay Area and AccuWeather places the expected maximum near 73°F, consistent with the month’s 69°F climatological average and recent model runs showing only modest warming. Recent heat advisories for interior valleys have not translated to the coast because of the stable marine influence, keeping probabilities for 74°F or higher below 20% while supporting the leading bin at 36.5%. Updated forecast discussions tonight and tomorrow morning will be the next key inputs for traders.