Recent National Weather Service and private model runs converge on an overnight low in the upper 50s for San Francisco on August 22, reflecting a moderately deep marine layer that limits radiative cooling while allowing modest mixing from onshore flow. This August’s reduced fog frequency—tied to warmer coastal waters and lingering El Niño influences—has produced slightly elevated humidity and less effective nocturnal chilling than the typical “Fogust” pattern, keeping lows near the 57 °F climatological average. Traders differentiate the tightly bunched 54–61 °F bins primarily on small forecast differences in inversion strength, wind speed, and exact marine-layer depth, all of which can shift the recorded minimum by a degree or two depending on the official reporting station. Updated model guidance and real-time observations through the night remain the key near-term catalysts.