Many people we encountered on this trail seemed to be misinformed about the nature of the trail. Several guidebooks describe it as a Waipo'o Falls trail, but the waterfall does not hold up to great expectations. You end up at the very top of the large Waipo'o Falls, but you don't get much waterfall action. There is a small falls just upstream from the large waterfall, but it's certainly nothing to write home about. If you come expecting a great waterfall perspective, you will be sorely disappointed. You should instead come for the excellent canyon views.
The area immediately uphill of the waterfalls includes an exposed ridge that can be seen from the Pu'u Hinahina Lookout before your hike (look for an orange ridge at the left edge of the canyon). This ridge affords excellent views across to the opposite side of the Waimea Canyon. These views make the trip more than worth the effort.
You should be advised that the trip is mostly downhill on the way out and uphill on the way back. We found that the trail was quite busy, and there were almost always people around us as we hiked. As with most other trails in this area, you'll want to pick a dry, clear day for this hike. You can get a feel for the weather in the mountains as you drive West along the main highway (50) before heading up into the mountains. Look to the North and check out the level of the clouds. If the clouds are covering the tops of the mountains, you might want to alter your plans, as you will likely find the viewpoints obscured by fog.
All in all, this trail makes for a nice half-day trip. It is doable for anyone in decent physical condition, and we even saw several children along the trail. You should be careful around the edge of the waterfall, as the ground is often crumbly and it is a long way down to the bottom. Speaking of the falls, we noticed that Waipo'o Falls was almost completely dry at the end of our trip (a few days after our Canyon Trail hike), so it is possible that you might find the waterfall nonexistent during your trip. Don't let this discourage you, as the views are well worth the effort!
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