Planning for the weather is a good way to make your trip to Cocos Island relaxing and enjoyable, especially when you're splurging. The hottest months are usually April and May, with an average temperature of 29°C, while the coldest months are August and July, with an average of 28°C. The rainiest months in Cocos Island are January, February, March and December, with each month seeing an average of 436 mm of rainfall.