Traders assign near-certainty to a 22°C high in Amsterdam on September 6 because official station data, including from Schiphol, recorded a daily maximum of 22.7°C under partly cloudy skies with light southerly flow. Numerical weather models such as GFS converged on this outcome, consistent with the seasonal climatology of roughly 20°C average highs and recent observational trends showing modest warming. The market-implied odds reflect real-time consensus backed by capital, incorporating the absence of significant frontal passages or advection that might alter peak readings. Unlikely revisions to verified station maxima or measurement errors remain the only realistic scenarios that could shift resolution.