Weather will likely play an important role when you plan your trip to Nueva Guinea, but bear in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually April and May, with an average temperature of 25°C, while the coldest months are February and January, with an average of 23°C. The rainiest months in Nueva Guinea are August, October, June and September, with each month seeing an average of 330 mm of rainfall.