**Forecast models and observations point to a lowest temperature for São Paulo on August 30, 2026, most likely between 17–20 °C, consistent with the tightly grouped market-implied odds around 17 °C or below (50.5 %), 19 °C (50 %), and 18 °C (48 %).** August marks the coolest part of the year in southern Brazil, with climatological nighttime minima typically near 12–14 °C, yet a persistent warm, dry air mass has elevated recent temperatures. Daytime highs reached or exceeded 30–32 °C under mostly clear skies and light winds, setting up moderate radiative cooling overnight. Current model consensus shows the temperature bottoming out near dawn or in the late evening at roughly 17–20 °C (about 63–68 °F), with hourly data indicating brief dips to 17 °C at some stations while others remain closer to 19–20 °C. Key differentiating factors include variable cloud cover that can trap heat, very light winds (often under 5 km/h) that limit mixing, and the precise location of the official reporting station. These elements create genuine uncertainty in the exact minimum, keeping the three leading outcomes nearly even. Traders are weighting the balance of numerical guidance from agencies such as the Brazilian weather service alongside real-time observations, with little probability assigned to outcomes outside the 17–19 °C range.