Iriomote in December

March through May offers Iriomote at its best – warm enough for swimming, cool enough for jungle hikes, and dry enough to keep the mosquitoes manageable. Temperatures hover around 75°F, perfect for kayaking through mangrove channels without breaking a sweat. October and November bring similar conditions after the summer heat breaks. The ocean stays warm from months of sun, but the humidity drops enough to make hiking pleasant. This is manta ray season too – your best shot at underwater encounters with these gentle giants. Avoid June through September unless you love heat, humidity, and typhoons. Summer temperatures hit 90°F with 90% humidity, turning every outdoor activity into an endurance test. Typhoon season peaks in August and September, when ferries cancel for days at a time. Winter (December through February) brings cool, dry weather perfect for hiking, but ocean activities lose their appeal when water temperatures drop to 70°F. Many tour operators reduce schedules or close entirely during these months.