Official observations from the Hong Kong Observatory recorded a daily maximum of 31°C on September 13, 2026, driving the near-certain market outcome. This aligns with typical late-summer conditions in the region, where September averages reach about 31°C under the influence of subtropical high pressure and warm sea surface temperatures in the northern South China Sea. Limited cloud cover and light winds prevented notable cooling, consistent with recent model runs showing stable thermal patterns. Trader positioning reflects strong confidence in these verified measurements, though rare post-event data revisions or station-specific anomalies could theoretically shift results.