Trader consensus on Polymarket tilts toward mid-60s highs for San Francisco on April 6, with 66-67°F leading at 29.5% amid closely matched outcomes reflecting uncertainty in National Weather Service forecast models. The GFS and ECMWF ensembles project peak temperatures in the 62-67°F range, driven by a persistent marine layer—cool, moist stratus clouds trapped beneath a temperature inversion from chilly Pacific upwelling—that typically caps spring highs around the April climatological average of 63°F. Differentiation hinges on morning fog burn-off timing and afternoon onshore wind speeds: prolonged stratus favors 62-63°F (18%), while earlier clearing and ridge-induced subsidence could push toward 66-67°F. New model runs every 6-12 hours from NOAA may sharpen these probabilities before resolution.