**Forecast consensus from multiple sources points to a low temperature in the upper 50s for Seattle on August 27, 2026, driving the market's heaviest weighting toward 58-59°F (51.0% implied probability).** National Weather Service, local meteorological services, and private models consistently project overnight lows in the mid-to-upper 50s under partly cloudy skies, light southwesterly winds (10-15 mph), and stable high pressure. Typical late-August climatology for Seattle (average low near 56°F) supports this range, with marine air from Puget Sound moderating temperatures and preventing sharper drops. Recent model runs show minimal spread, with no incoming cold fronts or clear-sky radiative cooling extremes that would push readings into the mid-50s or lower 60s. The 60-61°F bin (31.5%) captures upside risk from slightly stronger southerly flow or cloud cover retaining heat, while lower bins (56-57°F at 26.5%) reflect possible minor under-forecasting in drier air. Traders appear to be pricing the narrow forecast envelope and limited day-to-day changes observed through August 26, with the 58-59°F outcome emerging as the mode across official guidance. Resolution will hinge on the official minimum recorded at Sea-Tac or equivalent stations during the overnight period.