**Persistent marine layer conditions and typical late-summer coastal cooling are anchoring the 58-59°F range as the dominant outcome for San Francisco’s daily low on August 23, 2026.** Official forecasts from the National Weather Service and local observations indicate overnight lows in the upper 50s, with early-morning readings near 57–58°F under mostly cloudy skies and light southwest winds. This aligns closely with the climatological average low of 56°F for the date and recent August patterns showing minimal deviation. The compressed marine layer—maintained by the balance between Pacific troughing and interior ridging—continues to moderate temperatures without significant offshore flow or clear-sky radiative cooling that could push readings lower. No recent model shifts or atmospheric changes suggest a departure toward the mid-50s or below, keeping probabilities for 50–51°F and colder buckets minimal. Upcoming evening observations and any final NWS updates will refine the exact minimum, but current consensus supports the leading bucket.