Weather is probably a major factor when you plan your trip to Rarotonga, but bear in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually March and February, with an average temperature of 27°C, while the coldest months are August and September, with an average of 23°C. The rainiest months in Rarotonga are January, March, December and February, with each month seeing an average of 232 mm of rainfall.