Weather can make or break a road trip, so here's some data about year-round temperatures in Rotoava to help you plan yours: The hottest months are usually March and April, with an average temperature of 28°C, while the coldest months are August and September, with an average of 26°C. The rainiest months in Rotoava are February, January, December and November, with each month seeing an average of 204 mm of rainfall.