Weather is probably a major factor when you plan your trip to San Simon, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually March and April with an average temp of 77°F, while the coldest months are December and January with an average of 75°F. The rainiest months in San Simon are September, June, May, and October, with each month seeing an average of 10 inches of rainfall.