Persistent marine layer and onshore southwesterly flow from a weak low-pressure system are capping San Francisco highs near or below seasonal norms for September 2, with National Weather Service and local models projecting afternoon peaks of 65–70 °F under partly cloudy skies. This setup favors the closely matched 70–71 °F and 72–73 °F market bins, as the cool, humid air mass limits solar heating and suppresses the typical late-summer warming that historically produces 69–72 °F averages. Recent drizzle and stratus persistence through late August have reinforced trader expectations for limited inland heat advection, though any eastward shift in the marine boundary or reduced cloud cover could allow brief excursions into the mid-70s before resolution.