If you’re looking forward to lots of outings with your partner, take a look at these details about year-round temperatures in Potosi: The hottest months are usually October and November, with an average temperature of 10°C, while the coldest months are July and June, with an average of 7°C. The rainiest months in Potosi are January, December, February and March, with each month seeing an average of 187 mm of rainfall.