A cold front advancing across southern Brazil delivered cooler maritime air and light showers to São Paulo on September 6, 2026, producing an observed minimum near 7–8 °C at official stations. Model guidance from global ensembles showed a tight 2–3 °C spread in nighttime radiative cooling under overcast skies and moderate southeasterly flow, keeping the lowest temperature bracketed between 7 °C and 11 °C. Traders therefore assigned nearly equal implied probabilities to each integer outcome within that window while discounting extremes below 7 °C or above 11 °C. Updated surface observations and INMET station reports arriving on September 7 will resolve the exact minimum and determine which of the clustered contracts pays out.