Trader consensus on the highest temperature in San Francisco on September 29 shows tight clustering around 74–81°F, reflecting genuine forecast uncertainty just two days out. National Weather Service and NOAA model ensembles indicate variable marine-layer influence and onshore flow that could cap daytime highs near seasonal norms of 70–75°F, while any strengthening high-pressure ridge might allow modest warming. Recent GFS and ECMWF runs show slight divergence on afternoon wind patterns and cloud cover, keeping probabilities for 78–79°F and 80–81°F nearly even with cooler bins. Updated short-range guidance expected within 24 hours will likely refine these odds as resolution approaches.