Official National Weather Service observations from Seattle-Tacoma International Airport recorded a maximum temperature of 58°F on October 9, 2026, at 12:41 PM local time, aligning precisely with the market's dominant 58-59°F outcome at 99.8% implied probability. This reading fell 5°F below the 1991-2020 climatological normal high of 63°F amid light rain, fog, and easterly winds averaging 13 mph. Historical data show October 9 highs typically range 50-81°F, with the 2026 value near the lower end of recent variability. Official station measurements carry minimal uncertainty for market resolution, though minor discrepancies could arise from microclimate differences at non-airport sites or post hoc quality-control revisions.