Official National Weather Service observations from Seattle-Tacoma International Airport recorded a daily maximum temperature of 63–64°F on September 26, 2026, under mostly sunny to partly cloudy skies with light northerly flow and minimal precipitation. This measurement aligns with the market-implied 100% consensus on the 64–65°F bin, reflecting verified station data rather than forecasts. Late-September climatology shows an average high near 67°F, so the slightly cooler outcome stemmed from stable high pressure and suppressed onshore flow. Resolution hinges on the precise official reporting source and any station-specific adjustments; minor discrepancies between airport and urban sensors remain the primary uncertainty, though convergence on verified readings has eliminated alternative bins.