Weather is probably a major factor when you plan your trip to Wamena, but bear 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 temperature of 16°C, while the coldest months are August and July, with an average of 15°C. The rainiest months in Wamena are March, April, February and January, with each month seeing an average of 683 mm of rainfall.