Traders see the 25–26°C outcomes as nearly even because Mexico City’s high-elevation plateau (≈2,240 m) and mid-July rainy-season convection create narrow margins between these thresholds. Afternoon thunderstorms, driven by diurnal heating and moisture influx from the Pacific and Gulf, frequently develop by early afternoon and limit peak temperatures through cloud shading and evaporative cooling. Recent model guidance shows modest daytime instability with variable timing of convective initiation, allowing slight differences in insolation or storm onset to shift the daily maximum by 1–2°C. Historical July records cluster in the low-to-mid 20s, with occasional clearer periods permitting brief spikes near 26°C when storms are delayed.