Recent model consensus from the China Meteorological Administration points to increased cloud cover and scattered showers associated with the advancing Southwest Monsoon across the Pearl River Delta, limiting daytime heating and anchoring Shenzhen’s maximum temperature on May 17 near 26–28 °C. This pattern aligns with the climatological transition period when humidity rises sharply and solar insolation is reduced, producing a modal high several degrees below the late-May average of 29–31 °C. Trader probabilities reflect these dynamics, with 26 °C holding the slight edge because ensemble guidance favors persistent marine-layer influence over the coastal plain rather than clear-sky intensification. Updated short-range forecasts and Bao’an Airport observations tomorrow morning remain the key variables that could shift resolution between the tightly bunched 26–28 °C outcomes.