Trader sentiment clusters around 72–75°F for San Francisco’s August 4 high because National Weather Service and model guidance indicate a high-pressure ridge will deliver above-normal warmth while the persistent marine layer and onshore sea breeze moderate extremes. Coastal upwelling of cooler Pacific waters and afternoon westerly flow typically cap temperatures in the low-to-mid 70s even during regional heat events. Recent ensemble runs show modest spread tied to the exact position and strength of the ridge versus the sea breeze front, with drier air allowing brief afternoon peaks near 76–77°F possible if the gradient weakens. Historical August averages near 69°F provide context, yet the current synoptic setup supports the market’s tight distribution between the 70–71°F and 74–75°F bins.