Take a hat. They usually have walking sticks. Just go slow and say. Really recommend the free guided tour.
The hike is not too strenuous but there's almost no shade until you reach the waterfall and if you can't tolerate the heat it can be pretty exhausting during late spring/summer. I've hiked in July with temperatures above 110° F and I needed plenty of water and sunscreen to complete an hour long loop of the canyon.
Hike isn't a problem ...not sure about that waterfall always being there but there is another nearby hike where there is always waterfalls
If you do any hiking at all you'll have no problem.
There are times that its dry. Check at the ranger station before you pay to hike. Its a mild to moderate hike depending on what kind of shape your in.
Someone said that it's less this year but it was flowing well last Tuesday. The ground is often uneven and sometimes steep but a wide variety of people were making the trip. Some people were stopping for breaks but unless you are really out of shape or have bad legs, you'll make it.
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