Forecast models for Guangzhou show high uncertainty in the 48-hour window through September 17, with ensemble spreads reflecting competing influences from the western Pacific subtropical high and possible weak cold-air intrusions from the north. Current conditions feature typical late-summer warmth, but subtle shifts in steering flow or increased cloud cover and rainfall could suppress daytime highs and lower the daily minimum below 20 °C, while clearer skies and stronger southerly flow would favor readings at or above 30 °C. Historical September minima average near 24–26 °C, underscoring how modest changes in boundary-layer moisture and wind direction can swing outcomes across the tightly balanced market thresholds. Updated runs from agencies such as the China Meteorological Administration will likely clarify the signal ahead of resolution.