Official observations from the National Weather Service at Central Park place New York City’s September 13 high temperature at 80°F, directly supporting the market’s 100% implied probability on the 80-81°F outcome. This result aligns with the long-term climatological average of 77.5–79°F for the date, numerical weather model consensus showing no significant heat advection or blocking patterns, and mid-September conditions featuring moderate southerly flow without a heat dome. The narrow trading band reflects high confidence in these verified measurements rather than forecasts. Only a late data revision or station-specific anomaly outside the primary reporting network could realistically alter the outcome.