Traders are closely split between 68-71°F for San Francisco’s July 3 high because NOAA and National Weather Service short-range models show a persistent marine layer with moderate onshore flow keeping coastal readings near seasonal normals. Subtle differences in the strength of the Pacific high and the depth of the cool air mass will determine whether daytime warming reaches the low 70s or stalls in the upper 60s; stronger westerly winds and earlier fog clearance favor the higher bin, while a deeper stratus deck favors the lower. Historical July maxima average 68-72°F at downtown stations, and current ensemble guidance shows low spread around that range with resolution hinging on tomorrow’s 00Z model runs.