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 Bac Lieu: The hottest months are usually April and May, with an average temperature of 29°C, while the coldest months are January and December, with an average of 26°C. The rainiest months in Bac Lieu are October, September, July and June, with each month seeing an average of 284 mm of rainfall.