Weather will likely play an important role when you plan your trip to Las Piedras, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually September and October with an average temp of 80°F, while the coldest months are July and June with an average of 76°F. The rainiest months in Las Piedras are February, January, December, and March, with each month seeing an average of 17 inches of rainfall.