Planning for the weather is an important factor for making your trip to Lihir Island a success, especially when you're splurging. The hottest months are usually May and October, with an average temperature of 27°C, while the coldest months are August and September, with an average of 27°C. The rainiest months in Lihir Island are March, December, April and January, with each month seeing an average of 418 mm of rainfall.