Traders see near-equal implied odds for 70-71°F and 72-73°F highs in San Francisco on August 10 because official National Weather Service model guidance shows a narrow range centered near 71-72°F amid typical late-summer marine-layer variability. Onshore flow and a modest Pacific high-pressure ridge are expected to limit inland heating while allowing partial afternoon clearing, with wind speeds and the precise depth of the cool, moist marine layer serving as the key variables that differentiate the two leading bins. Historical climatology places August daily maxima around 69-70°F at downtown stations, so any slight delay in fog burn-off or stronger sea breeze could cap readings at the lower end, whereas reduced cloud cover would push toward the mid-70s. New model runs and updated NWS forecasts through the evening of August 9 remain the next data points likely to shift positioning.