The Yungas have two seasons. The dry season (May to October) has clearer skies, easier hiking, more reliable mountain biking on the Death Road, and the famous views over the valleys. Nights are cool (10–15°C) but days are warm and sunny. This is by far the better season to visit and the period when most travellers arrive.
The rainy season (November to April) is hot, humid, and frequently cloudy. Trails turn to mud, landslides are common, and the views vanish behind cloud for days at a time. It is still beautiful — flowers, butterflies, dramatic clouds in the valleys — but the practical drawbacks are real. April is a good shoulder month: the rains are easing and the forest is at its lushest.
The town celebrates its patronal festival at the end of October with three days of dancing, brass bands, and parades. Worth timing a visit around if you can.