Mauna Loa Observatory Trail

The full round-trip hike to the summit via the Mauna Loa Observatory Trail is approximately 12.6 miles and can take around 6 hours to complete as a very challenging day trip. However, due to the high altitude and rugged terrain, many hikers prefer to make it an overnight trip.

This trail is rated as difficult. It's considered one of the most challenging hikes in Hawaii due to its high altitude, strenuous walking over rough lava fields, and unpredictable weather conditions. Acclimatization to the altitude is crucial.

The terrain is largely rugged and unstable, traversing vast lava fields, including both smooth pahoehoe and rough 'a'a lava. It's often described as a 'lunar-like landscape.' While some sections might have an old dirt road or greenish sand, expect mostly unforgiving lava. The path is marked by cairns (ahu) and occasional signs.

You'll experience an otherworldly landscape characterized by vast expanses of lava flows with interesting variations in colors and textures. Due to the high altitude, vegetation is sparse, offering stark beauty. Expect breathtaking views of the immense Mokuʻāweoweo, Mauna Loa's summit caldera, and distant views towards Mauna Kea. Fumeroles can also be seen in the summit caldera.

The trail begins near the Mauna Loa Observatory. Parking is available, but hikers should park carefully to avoid interfering with the observatory's sensitive instruments. There are no shuttles mentioned, so personal vehicle access is required.

Yes, the Mauna Loa Observatory Trail is located within Hawaiʻi Volcanoes National Park. Therefore, you will need to pay the park entrance fee. Additionally, permits are required for overnight stays in the backcountry, including at the cabins. Check the nps.gov website for the most current information on fees and permit requirements.

While often sunny above the inversion layer, snow, strong winds, and driving rain are possible at any time of year due to the high altitude. There isn't a single 'best' season, but clear weather windows are ideal. Always check the forecast immediately before your hike and be prepared for rapidly changing conditions.

No, dogs are generally not permitted on backcountry trails within Hawaiʻi Volcanoes National Park, which includes the Mauna Loa Observatory Trail. Service animals are an exception, but pet dogs are not allowed.

Yes, the trail offers unique features. You'll start near the Mauna Loa Observatory. The route provides an unparalleled opportunity to experience the 'bare bones of the earth' on the world's most massive active volcano. For overnight trips, the Mauna Loa Summit Cabin is accessible via a spur trail from the North Pit intersection.

There are no dependable natural water sources along the trail. The only potential water source is at the Mauna Loa Summit Cabin, but this water needs purification and its availability can vary. Hikers must carry ample water for the entire duration of their trip.

The primary challenges include significant high altitude (starting at 11,040 ft and reaching 13,680 ft), which can cause altitude sickness. The strenuous walking over rough, unstable lava is exhausting. Additionally, unpredictable weather with strong winds, rain, or even snow can make conditions difficult and navigation tricky.