Weather can make or break a road trip, so here's some data about year-round temperatures in Mamai to help you plan yours: The hottest months are usually January and February, with an average temperature of 27°C, while the coldest months are August and July, with an average of 25°C. The rainiest months in Mamai are January, February, March and December, with each month seeing an average of 371 mm of rainfall.