Are ordinary hiking leggings warm enough for the Mount Rinjani summit?

No, ordinary hiking leggings are not warm enough on their own for the Rinjani summit. Leggings, even thermal ones, are a base layer in this system. With an estimated 0 to 4 degrees Celsius on the predawn climb and near-freezing air at 3,726 meters, plus wind on the exposed ridge, you need hiking trousers over them and ideally a wind layer too.

The standard local packing list is explicit about this: it includes thermal top and bottom plus insulation and a shell. The thermal bottom is the base, exactly like the leggings, and the insulation and shell are what make the system work in the stopped minutes. Trekkers who climb in leggings alone usually regret it on the summit pause, where the wind strips heat fast from any single-layer fabric, and the descent then starts with legs already chilled.

What works is the same logic you apply above the waist. Thermal leggings under hiking trousers give you a warm, moving-friendly combination for the climb; add wind protection if your trousers are thin. Fit matters over a long itinerary: check the seams and waistband on a few hours of walking, because a full traverse covers about 33 kilometers and the rim camp at about 2,639 meters is already cold in the evening, so your leg layers get worn at dinner, in the tent and through the summit night, not just for the push.

A note on expectations: this is not a mountain where you choose between comfort and style; it is a mountain where you choose layers. If you love hiking in leggings, bring them, and bring trousers too, because the summit is the coldest hour of your trip and it rewards whoever dressed for it. Our guides check kit at the briefing and will flag missing leg layers immediately, because underdressed legs on summit night are one of the small errors that turn a good trek into an endurance test.