Weather will likely play an important role when you plan your trip to Tena, but bear in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually September and October, with an average temperature of 19°C, while the coldest months are July and August, with an average of 18°C. The rainiest months in Tena are April, May, June and March, with each month seeing an average of 431 mm of rainfall.