Weather is probably a major factor when you plan your trip to San Juan de Pasto, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually September and August with an average temp of 62°F, while the coldest months are August and July with an average of 62°F. The rainiest months in San Juan de Pasto are April, March, May, and November, with each month seeing an average of 18 inches of rainfall.