Recent numerical weather prediction models, including updated runs from global ensembles, form the core driver behind the market's tight clustering around 25–26°C for Mexico City's August 21 high, with implied probabilities reflecting modest upward deviation from the long-term August average of roughly 23–24°C. Mexico City's high-elevation plateau setting (approximately 2,240 m) produces large diurnal ranges, where daytime maxima depend heavily on incoming solar radiation, boundary-layer moisture, and afternoon convective cloud development during peak rainy season. Key differentiating variables include forecast timing of any showers, which can suppress peaks by several degrees, versus clearer intervals that allow greater warming; model consensus shows limited spread but acknowledges typical uncertainty in mesoscale precipitation placement. Traders are weighting the latest guidance showing highs near 25.5–26°C, with fresh model updates and observational data from local networks expected to refine resolution criteria before market close.