If you’re looking forward to lots of outings with your partner, take a look at these details about year-round temperatures in Chia: The hottest months are usually September and January, with an average temperature of 14°C, while the coldest months are January and December, with an average of 14°C. The rainiest months in Chia are November, April, March and October, with each month seeing an average of 353 mm of rainfall.