Planning for the weather is a good way to make your trip to Buka Island relaxing and enjoyable, especially when you're splurging. The hottest months are usually January and February with an average temp of 78°F, while the coldest months are September and August with an average of 76°F. The rainiest months in Buka Island are August, April, July, and March, with each month seeing an average of 22 inches of rainfall.