Recent ensemble forecasts from the China Meteorological Administration and European Centre for Medium-Range Weather Forecasts indicate a Beijing high near 25–26 °C on May 19, driving the near-even market split between those two outcomes. Mid-May climatology features strengthening southerly flow that can advect warmer air from the North China Plain while daytime insolation and reduced cloud cover allow rapid surface heating after 11 a.m. local time. Key variables still in flux include the precise timing of any frontal passage, boundary-layer mixing depth, and urban heat-island amplification, each of which can shift the observed maximum by 1–2 °C. Updated model runs and official guidance expected later today will likely tighten the range and determine whether traders continue to favor the 25 °C or 26 °C contract.