If you’re hoping to get lost in the rain on your romantic getaway, take a look at these details about year-round temperatures in Santa Lucia: The hottest months are usually April and March, with an average temperature of 22°C, while the coldest months are January and December, with an average of 20°C. The rainiest months in Santa Lucia are May, June, September and October, with each month seeing an average of 391 mm of rainfall.