Singapore’s equatorial climate produces consistently high humidity and limited seasonal temperature swings, with September averages near 31.6°C and historical daily maxima rarely exceeding 34–35°C absent unusual atmospheric conditions. Current numerical weather models from multiple agencies converge on a September 5 high around 31–32°C under southeasterly flow and partly cloudy skies, with only modest afternoon heating expected before typical convective showers develop. The near-even market split between 38°C+ and 28°C-or-below outcomes therefore captures traders’ recognition that small shifts in cloud cover, moisture convergence, or model bias could push the observed maximum a few degrees in either direction, while the flat pricing across intermediate bins reflects the narrow historical distribution around the mean. Updated local observations and the next model runs will clarify whether steering patterns or localized heating alter this baseline.