**Marine layer persistence and onshore flow are the dominant factors anchoring trader sentiment near 70–73°F for San Francisco’s June 15 high.** Official guidance from NWS and recent model consensus point to a classic June Gloom setup, with the marine inversion and westerly winds off the cool Pacific keeping daytime maxima in the mid-to-upper 60s at KSFO, though localized warming in sheltered areas or brief clearing could push readings 2–4°F higher. Historical climatology shows a normal high of 72°F, yet persistent stratus and 55–57°F dew points limit radiative heating. The tight clustering between 70–71°F and 72–73°F reflects uncertainty over exact timing of any afternoon sun breaks versus renewed fog intrusion, with lower-probability tails capturing rare offshore wind shifts or model bias toward warmer solutions. Updated NHC-adjacent guidance and morning soundings tomorrow will refine these narrow ranges.