Weather will likely play an important role when you plan your trip to Serra, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually February and March with an average temp of 77°F, while the coldest months are July and August with an average of 70°F. The rainiest months in Serra are December, November, October, and March, with each month seeing an average of 7 inches of rainfall.