Trader consensus on Polymarket prices a 78.5% implied probability for San Francisco's highest temperature reaching 78°F or higher on April 4, driven by a strengthening high-pressure ridge over the West Coast that promotes subsidence warming and clear skies, as detailed in recent National Weather Service forecasts for the Bay Area. Following a record-warm March—San Francisco's hottest on record with peaks near 86°F—a brief cooldown has ended, with April 3 observations and models showing highs near 74°F today amid light winds and sunny conditions, setting up further inland heat advection. Ensemble guidance from NOAA models like GFS and ECMWF aligns on 10-20°F above the April climatological normal of around 63°F at SFO, though coastal marine layer persistence or unexpected onshore flow could cap peaks at 76-77°F (14.5% odds). Updated NWS advisories expected later today may refine this outlook prior to resolution.