Recent National Weather Service and model guidance point to a high near 70–73°F in San Francisco on September 17, driven by morning low clouds or patchy fog giving way to partial afternoon clearing under light southerly to westerly winds. This pattern aligns with typical late-summer marine-layer influence that moderates coastal maxima near the 1991–2020 September average of about 71°F. The tight spread between the leading 70–71°F and 72–73°F bins reflects uncertainty in the exact timing of clearing and any residual onshore flow strength, both of which can suppress or allow brief warming. Updated short-range model runs and NWS forecast discussions expected overnight will likely refine the peak temperature and shift market-implied odds accordingly.