If you’re looking forward to lots of outings with your partner, take a look at these details about year-round temperatures in Anjouan: The hottest months are usually March and December, with an average temperature of 28°C, while the coldest months are August and September, with an average of 25°C. The rainiest months in Anjouan are January, February, March and December, with each month seeing an average of 230 mm of rainfall.