If you’re looking forward to lots of outings with your partner, check out these details about year-round temperatures in Nanaimo: The hottest months are usually August and July with an average temp of 62°F, while the coldest months are December and February with an average of 39°F. The rainiest months in Nanaimo are November, January, December, and October, with each month seeing an average of 9 inches of rainfall.