A cold air mass has driven a sharp temperature decline across Beijing on October 13, with official forecasts from the Beijing Meteorological Station indicating clear skies, northerly winds gusting to 6 on the Beaufort scale, and enhanced radiative cooling overnight. This setup supports an expected urban low near 8°C, with mountain areas potentially reaching 3–6°C, aligning with the market's near-certain consensus on 6°C or below. Historical climatology for mid-October shows similar intrusions can produce rapid drops of 5–8°C within 24 hours when paired with dry conditions and light winds. Realistic challenges include revised observational data from urban heat islands pushing the minimum above the threshold or late forecast adjustments from the National Meteorological Center if steering patterns shift.