Latest National Weather Service guidance points to a San Francisco high near 68–70°F on August 18, with the marine layer and onshore sea breeze expected to limit warming. Trader consensus favoring the 70–71°F bracket at 30.5% reflects model spreads and occasional afternoon clearing that can allow brief warming before the layer redevelops. Key differentiators include the strength and timing of the inversion capping the marine stratus, wind direction shifts that modulate the sea breeze, and microclimate variations across the city versus official reporting stations. Historical August averages hover around 67–70°F, underscoring why outcomes above 75°F carry low implied probability absent a significant forecast shift. Updated model runs and evening NWS briefings remain the primary near-term catalysts.