Mount Rinjani can get surprisingly cold, especially near the crater rims and at the summit. Temperatures at the top often drop to around 5°C to 10°C, and with wind chill it can feel even colder. The summit push happens in the early morning hours when the air is at its coldest, and strong winds are common on the exposed volcanic ridge. Many hikers are shocked by how quickly the temperature changes after leaving the warm lowlands of Lombok.
At the Sembalun and Senaru crater rims, nighttime temperatures are usually between 8°C and 12°C, but winds can make it feel much colder. Inside the tent it is chilly, and proper warm clothing is essential for a good night’s sleep. In contrast, the daytime temperatures on the lower parts of the trail are much warmer, often around 20°C to 30°C, creating a big difference between the base and the upper sections of the mountain.
Because of these temperature swings, hikers must bring warm layers, gloves, a hat, and a proper jacket. Even though Indonesia is a tropical country, the high altitude and exposed terrain on Rinjani create alpine-like conditions near the top. Being prepared for cold nights and a freezing summit morning is a key part of staying comfortable and safe during the trek.
