Recent National Weather Service and regional model consensus for Mexico City points to a highest temperature on June 21 near 23–26 °C amid the onset of the rainy season, which has driven the market’s tight clustering around 24 °C (24.5 %), 25 °C (35.5 %), and 26 °C (24.5 %). Afternoon convection and increasing cloud cover typically cap daytime maxima several degrees below late-spring peaks, while historical June averages of 24–25 °C and the last week’s observed highs in the same range reinforce this range. Updated short-range guidance shows limited day-to-day variability, keeping probabilities for outcomes outside 23–26 °C below 10 % each. Traders are therefore weighting the most likely forecast envelope rather than outlier model runs.