Recent National Weather Service model guidance projects daytime highs in San Francisco reaching the low to mid-70s on May 19, driven by a weakening marine layer, reduced onshore flow, and warmer southerly advection that allows greater afternoon mixing and solar heating. This positions the 66°F-or-higher outcome as the clear market consensus at 95.8% implied probability, well above the May climatological average high of 67°F at San Francisco International Airport. Historical analogs show similar offshore warming episodes can push peaks 5–8°F above normal when low clouds dissipate early. Traders are watching the next 48-hour forecast updates and real-time KSFO observations for any late marine intrusion that could cap the peak closer to 65°F and shift probabilities modestly lower.