Forecast models from the National Weather Service and private sources point to a San Francisco high near 70–72°F on August 16, consistent with the market’s tight clustering around those bins. Persistent onshore flow from the cold California Current and a shallow marine layer limit daytime heating, producing the city’s characteristic cool summer regime even under weak high pressure. Slight differences between 70–71°F and 72–73°F hinge on how completely the stratus clears, the strength of the sea breeze, and boundary-layer mixing; any delay in fog dissipation or stronger westerlies would favor the lower outcome. Historical August normals near 68–70°F at downtown and airport stations underscore why traders see limited upside beyond 73°F absent an unusual offshore flow event.