Recent ensemble forecasts from the Hong Kong Observatory and international models place the May 17 maximum near 25–26°C, driving the tight clustering of implied probabilities around those outcomes. A stable subtropical high-pressure ridge combined with residual moisture from prior thunderstorms and a persistent low-pressure trough over the northern South China Sea maintains easterly winds of force 4–5, sustaining 75–95% relative humidity and widespread cloud cover that limits daytime solar heating. Minor variations in model timing of trough weakening or cloud break-up introduce the small spread toward 27°C, while historical May climatology shows typical maxima of 27–29°C under clearer conditions. Updated runs tomorrow morning will refine the final resolution range.