Official Japan Meteorological Agency observations for Tokyo on October 13, 2026, recorded a minimum temperature of 20°C, aligning with the market's near-100% implied probability on that exact threshold. Persistent mild southerly flow, elevated dew points near 18–19°C, and limited radiational cooling under mostly cloudy skies prevented further overnight drops, consistent with late-autumn climatology for the region where average October lows hover around 15–17°C. Numerical weather prediction consensus from global and regional models showed minimal spread around this value, with no significant cold-air advection or clear-sky conditions emerging to alter the outcome. A late data revision or station-specific anomaly remains the only realistic scenario that could shift resolution, though such adjustments are historically rare for daily minimums.