Trader consensus on Polymarket favors a high temperature of 64-65°F at 41% implied probability for San Francisco on May 1, driven by National Weather Service short-range forecasts and ensemble model guidance projecting peak daytime readings in the mid-60s amid persistent marine layer stratus. Cool sea surface temperatures off the California coast, around 55-57°F, combined with moderate onshore winds of 10-15 mph, limit boundary layer mixing and suppress heating, aligning with early May climatology where average highs at downtown stations average 65°F and rarely exceed 70°F. Recent April trends, including below-normal highs in the low 60s and lingering low clouds from a stalled upper-level trough, have reinforced this positioning, lowering odds for 68°F or higher to 7%. Watch for afternoon burn-off potential in final 18z model runs today, which could nudge toward 66-67°F if winds weaken.