NWS forecasts and model consensus point to a San Francisco minimum near 57°F on August 23, shaped by the stable marine layer that has kept recent overnight lows at 56°F. Cold California Current waters and coastal upwelling maintain ocean temperatures near 55–58°F, while the North Pacific High sustains a temperature inversion that traps cool, moist air onshore through the Golden Gate. Light westerly winds and mostly cloudy conditions limit nighttime radiative cooling, narrowing the range between 56–59°F bins where trader probabilities cluster tightly. Small shifts in marine layer depth or wind timing could tip the exact minimum, with updated model runs and evening observations the next key data points.