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 Santiago do Cacém, Santa Cruz e São Bartolomeu da Serra: The hottest months are usually August and July, with an average temperature of 21°C, while the coldest months are February and January, with an average of 13°C. Average annual precipitation for Santiago do Cacém, Santa Cruz e São Bartolomeu da Serra is 607 mm.