Weather will likely play an important role when you plan your trip to San Fernando, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually September and May with an average temp of 81°F, while the coldest months are January and February with an average of 79°F. The rainiest months in San Fernando are August, July, November, and October, with each month seeing an average of 7 inches of rainfall.