The closely matched market-implied odds favoring minimum temperatures of 24–26°C stem from Hong Kong’s subtropical May climatology, when the northeast monsoon weakens and the Pacific subtropical high begins steering warmer, more humid air northward. Official long-term records from the Hong Kong Observatory show average overnight lows near 24.5°C during this transitional period, with interannual variability of roughly ±2°C driven by cloud cover, rainfall timing, and boundary-layer moisture. Current global forecast ensembles indicate modest diurnal cooling under partly cloudy skies and light easterly flow, keeping the bulk of probability within that narrow band while leaving room for a 1–2°C shift if nocturnal showers or clearer conditions materialize. Updated model runs and local mesoscale guidance expected over the next 48 hours will refine these variables ahead of market resolution.