Koror weather in September

Palau's forum is consistent that September, deep in the June-to-September wet season, means hot, humid days with regular showers - but divers specifically noted the rain rarely affects underwater visibility, and diving and snorkeling stay world-class regardless. Showers usually blow through quickly rather than settling in for the day, though an occasional non-stop rainy day does happen. Wind is the more relevant factor for outer-reef dive sites like Blue Corner, which can get called off for a day when it's too rough, but conditions elsewhere usually stay diveable.

Forum posters name December-March as Palau's relatively drier season and call March-May specifically a good window to visit, though 'dry' here is relative - rain remains a near-daily possibility even in this stretch, just somewhat less of one than the wetter mid-year months, and posters are clear it doesn't meaningfully affect diving schedules either way. One visitor arriving right at the end of February into early March reported fine weather overall, with the occasional quick shower followed by strong sunshine rather than sustained rain. Diving is the clear headline draw regardless of the exact week - Blue Corner, the German Channel and Ulong Channel come up repeatedly as must-do sites, with posters consistently praising the marine life and reef conditions this time of year.