Official National Weather Service observations from Austin stations, including Bergstrom International Airport recording a daily maximum of 78°F, established the 78-79°F range as the verified high for October 3, 2026. This placed temperatures about 9°F below the 1991-2020 normal of 87°F, consistent with a cooler air mass and increased cloud cover limiting daytime heating. Market-implied odds reached 100% because these authoritative measurements from calibrated instruments align precisely with resolution criteria, leaving minimal room for revision. Only an unexpected post-publication data correction or alternate station weighting could alter the outcome, though such changes remain rare once preliminary climate summaries are issued.