Late August in the Sichuan Basin keeps Chengdu under a persistent warm, moist airmass typical of the East Asian monsoon’s tail end, with climatological daily highs averaging 31–34 °C and occasional peaks near 35–36 °C. Two-day forecast uncertainty stems mainly from variable convective cloud cover and scattered showers that can suppress afternoon maxima by 1–3 °C or allow brief clearing that pushes readings higher. Recent model runs show the heat ridge holding but with modest cooling signals by month’s end, while the urban heat-island effect and topographic trapping of humidity add further variability around the 32–34 °C corridor. Equal market-implied odds across bins therefore reflect genuine dispersion in short-range guidance rather than any single dominant catalyst.