If you’re hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Calamba: The hottest months are usually May and April with an average temp of 83°F, while the coldest months are January and February with an average of 79°F. The rainiest months in Calamba are July, September, August, and June, with each month seeing an average of 12 inches of rainfall.