Yes, warm clothes are absolutely necessary for Mount Rinjani. Even though Lombok is a tropical island with warm weather at sea level, the temperatures on Rinjani drop sharply as you climb higher. Nights at the Sembalun and Senaru crater rims are cold, usually between 8°C and 12°C, and the early-morning summit push can feel close to freezing with strong winds. Without proper warm layers, most hikers struggle to stay comfortable during the night and at the summit.
Warm clothing should include a fleece or insulated jacket, long pants, a warm hat, gloves, and a base layer for sleeping. These items make a big difference in comfort and safety, especially when waiting for sunrise at the summit in windy conditions. Even hikers who are used to cooler climates are often surprised by how cold it feels at 3,700 meters in Indonesia.
Having the right warm gear is just as important as having good hiking shoes or a headlamp. The mountain environment changes quickly, and being prepared ensures a far better experience throughout the trek.
