Weather is probably a major factor when you plan your trip to Lihir Island, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually May and October with an average temp of 81°F, while the coldest months are August and September with an average of 80°F. The rainiest months in Lihir Island are March, December, April, and January, with each month seeing an average of 16 inches of rainfall.