Recent numerical weather prediction models from the China Meteorological Administration and international ensembles indicate a daily high temperature in Beijing on May 18 most likely settling between 26 °C and 27 °C under partly cloudy skies with light southerly flow. This near-even split between the two leading outcomes reflects genuine forecast uncertainty at the 24-hour horizon, where small variations in boundary-layer mixing, cloud cover, or the exact timing of a weak frontal passage can shift the maximum by 1 °C. Historical May climatology for Beijing shows an average high near 28 °C, so current conditions represent a modest negative anomaly driven by residual cool air behind an earlier trough. Updated model runs issued overnight and morning observations from surface stations will provide the final inputs for market resolution.