Official National Weather Service observations for Denver on September 19, 2026, recorded a daily maximum of 77°F, reached in the mid-afternoon under partly cloudy skies with light winds and only trace precipitation. This value sits just below the 1991–2020 climatological normal high of 79°F and aligns precisely with the market’s dominant 76-77°F outcome. Traders priced in near-certainty because preliminary and final NWS climate summaries issued that evening confirmed the reading across primary stations, leaving minimal room for measurement revisions or alternative station data. The only realistic challenges would involve an unusual post-event correction to the official report or a market resolution rule favoring a secondary sensor, both of which are historically rare for this type of temperature contract.