The closely matched market-implied probabilities around 200–220 mm reflect substantial uncertainty in Hong Kong’s remaining May rainfall, driven by the highly variable onset of the southwest monsoon and frequent afternoon convective thunderstorms. Official seasonal forecasts from the Hong Kong Observatory indicate normal to above-normal totals for May–July, consistent with the region’s climatological average of roughly 290 mm, yet short-term model runs show mixed signals on monsoon trough positioning and moisture influx from the South China Sea. Historical data reveal wide interannual swings, from under 50 mm in dry years to over 500 mm when persistent troughs or early tropical systems develop. Traders are weighing the potential for intensified showers in the final two weeks against the possibility of suppressed activity if subtropical high pressure strengthens. New weekly forecasts and observational updates through late May will likely clarify whether totals trend toward the lower or upper side of the current consensus range.