National Weather Service forecast models have consistently projected a daily high of 66–67°F in New York City on May 21, following a brief heat wave with highs in the 90s on May 18–20. Stable high-pressure systems and limited moisture advection suppressed warming, producing cooler northerly flow and clear skies that aligned with climatological norms for late May. This strong model consensus, backed by multiple runs and surface observations, drove trader sentiment toward the 66–67°F outcome at near-100% implied probability. Unexpected shifts in steering patterns or delayed frontal passage could have allowed modest warming above 68°F, though current data show low likelihood of such revisions.