Trader consensus on Polymarket reflects high uncertainty for San Francisco's highest temperature on April 9, with nearly even implied probabilities across outcomes driven by divergent short-range forecast models and the city's persistent marine layer influence. National Weather Service guidance shows a warming trend from recent high pressure ridging, pushing early April highs toward the mid-60s°F amid reduced onshore flow, but ensemble spreads in GFS and ECMWF runs indicate potential for cooler 50s°F if stratus clouds linger or a weak trough approaches mid-week, as hinted in latest discussions. Key differentiators include fog burn-off timing, Pacific sea surface temperatures near 55°F, and coastal wind advection; climatological April highs average 62°F at SFO airport, where observations resolve the market. Watch daily 12z NWS updates for refined guidance.