**Marine layer moderation and typical August climatology position the lowest temperature in San Francisco on August 26, 2026, near the historical average low of 56°F.** Official forecasts from sources including the National Weather Service and local models project overnight lows of 56–58°F under partly cloudy to mostly clear conditions, with early-morning readings already near 57–58°F at monitoring sites like San Francisco International Airport. This aligns with the market’s leading 56–57°F bin (57% implied probability) and the adjacent 54–55°F outcome (26%). San Francisco’s coastal setting and prevailing westerly flow sustain cool marine air and frequent fog or low stratus, limiting radiative cooling while preventing significant warming. Historical data confirm an average August 26 low of 56°F and an all-time minimum of 50°F, so current conditions reflect near-normal variability without strong anomalies such as an offshore flow event or anomalous marine layer depth. Recent model consensus shows stable steering patterns and no major forecast shifts in the past 24–48 hours, supporting the tight clustering of probabilities around the mid-50s. Traders appear to price the high likelihood of resolution within the 54–57°F range based on these established atmospheric controls and real-time observations.