**Forecast models for São Paulo on August 26, 2026, converge on an overnight minimum near 14–16°C under mostly overcast skies, light southeasterly flow, and possible late showers.** These conditions produce the tight clustering of market-implied odds around 14°C (26.5%), 15°C (29.5%), and 16°C (31.5%), as small differences in cloud timing or boundary-layer mixing can shift the exact low by 1–2°C. Persistent high pressure and limited daytime heating from cloud cover keep temperatures below late-August climatological norms of roughly 21–23°C highs and 13–14°C lows. Radiative cooling at night is moderated by increased moisture and wind, while any passing cold front or enhanced cloud cover could push readings toward the lower end of the range. Official guidance from regional models shows modest spread, leaving traders to weigh near-term variables such as the strength of southeasterly advection of maritime air versus clearer intervals that might allow slightly greater cooling. Historical August minima at the São Paulo-Guarulhos reference station rarely fall below 11°C or exceed 17°C, explaining the low probabilities assigned to extremes. The next model runs and any updated INMET or NHC-adjacent guidance will likely refine the precise threshold.