Clear skies and light southerly winds under a stable high-pressure system have driven Beijing's daytime maximum to 28°C on September 15, aligning with consensus forecasts from the China Meteorological Administration. Multiple model runs and observational data through the afternoon confirm peak readings near this threshold, consistent with seasonal norms for mid-September and the absence of cloud cover or frontal activity that could suppress insolation. Trader consensus at 100% for 28°C reflects this tight convergence of verified measurements and short-range guidance. A sudden increase in humidity, unexpected convective development, or station-specific microclimate effects could theoretically shift the official high, though current atmospheric conditions make such deviations improbable before resolution.