Weather will likely play an important role when you plan your trip to San Nicolás, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually April and March with an average temp of 75°F, while the coldest months are January and December with an average of 72°F. The rainiest months in San Nicolás are October, May, September, and June, with each month seeing an average of 14 inches of rainfall.