Mid-May rainfall accumulation in Hong Kong remains near or slightly below the long-term climatological average of 250–300 mm for the full month, with traders weighing the Hong Kong Observatory’s seasonal outlook for normal to above-normal precipitation through July. The closely matched market-implied odds around 180–220 mm bins reflect substantial uncertainty in the remaining two weeks, driven by the onset of the East Asian summer monsoon and variable steering patterns that could either enhance convective activity or suppress totals. Model guidance shows typical divergence in rainfall projections for late May, while historical analogs indicate that single-day deluges or the absence of organized systems can swing monthly totals by 50–100 mm. Resolution hinges on official Hong Kong Observatory totals through May 31, with fresh forecast updates expected to sharpen consensus in the coming days.