It is not allowed to hike Mount Rinjani during the official rainy-season closure from January to March, and the mountain usually reopens around April 1 once conditions become safe again. During these months the trails are too slippery, landslide risk is high, and heavy storms make navigation difficult. Park authorities close the mountain every year to protect hikers and to allow the natural environment to recover after months of rain.
Outside of the official closure, it is still possible to encounter rain at any time of year. Even during the dry season a sudden shower can move through the mountain, especially in the afternoons. For this reason, trekkers should always be prepared with rain protection, waterproof layers, and dry bags for their gear. The climate in Rinjani’s highlands is unpredictable, and quick weather changes are common because of the mountain’s height and exposure.
November and December deserve special attention because they mark the transition into the rainy season. These two months can still offer good days for trekking, but conditions become more unstable. Cloud cover increases, trails begin to soften, and rainstorm frequency rises. People who hike during this period should expect wet sections on the trail and a higher chance of poor visibility, especially near the crater rim or summit.
The overall guideline is simple. You cannot hike Rinjani between January and March, but you should always remain prepared for rain no matter which month you choose. Travelling with a trained guide helps a lot during unpredictable weather because guides know how to time the route, adjust the pace, and make decisions based on safety. If you choose to hike in the months close to the rainy season, proper gear and careful planning become even more important.
