The Hong Kong Observatory's confirmed observations, recording a daily maximum of exactly 27°C multiple times on May 15 amid persistent cloud cover, high humidity levels of 83–89 percent, and active thundery showers triggered by a low-pressure trough, have driven the market's overwhelming 99.9 percent implied probability for this outcome. Subtropical May conditions typically feature daytime highs near 28°C, yet intense convective activity and moist southerly flow effectively suppressed further solar heating and prevented any surge toward 28°C or higher. This alignment with official station data and forecast model consensus leaves minimal room for deviation, though an improbable late-day clearance of skies and reduced precipitation could theoretically allow brief additional warming before the final tally.