Weather will likely play an important role when you plan your trip to Calamba, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually May and June with an average temp of 81°F, while the coldest months are February and January with an average of 79°F. The rainiest months in Calamba are January, December, October, and November, with each month seeing an average of 12 inches of rainfall.