Official National Weather Service observations at Seattle-Tacoma International Airport recorded a minimum of 55°F on September 8 under clear skies and high pressure, aligning closely with seasonal normals and supporting the market's strong 92.5% implied probability on 56-57°F. Recent model consensus from NOAA and local forecasts emphasized light northerly winds, minimal cloud cover, and temperatures holding near or slightly above the 1991-2020 average low of 54.4°F, with no significant cool-air advection or marine influence to drive further drops. Trader positioning reflects this data stability and low forecast uncertainty near resolution. A late station adjustment or measurement at an urban site recording a degree lower could shift the outcome toward 54-55°F, though such revisions remain uncommon for this location and date.