The best time to go to Kiunga is during the dry season, which runs from May to November.
During these months, you'll experience lower humidity and less rainfall, making it much more comfortable for exploring the region. The drier conditions also mean that rivers are less swollen, which is ideal if you're planning any boat trips or activities on the Fly River. This period is particularly good for wildlife spotting, as animals are more active and easier to see near water sources.
For those interested in birdwatching, specifically, the dry season offers the best opportunities to see the region's diverse birdlife, including various species of birds of paradise.