Weather is probably a major factor when you plan your trip to Ourinhos, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually December and September with an average temp of 74°F, while the coldest months are July and June with an average of 65°F. The rainiest months in Ourinhos are January, February, December, and November, with each month seeing an average of 8 inches of rainfall.