Weather will likely play an important role when you plan your trip to Puerto Rico, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually February and January with an average temp of 79°F, while the coldest months are July and June with an average of 75°F. The rainiest months in Puerto Rico are May, April, June, and July, with each month seeing an average of 15 inches of rainfall.