Recent model consensus from the Hong Kong Observatory and global ensembles points to a daytime maximum temperature on May 18 most likely between 26–28°C, reflecting the subtropical monsoon regime's transition with southerly flow from the South China Sea and moderate humidity that caps solar heating. Persistent cloud cover and scattered showers, typical for mid-May, further suppress peak readings below the seasonal average high near 29–31°C. Traders assign roughly equal weight to 26°C, 27°C, and 28°C outcomes because small shifts in upper-level steering or timing of any frontal passage could alter the exact high by 1–2°C, while the low probabilities on extremes underscore limited historical precedent for outliers this early in the warm season.