Dry, and dusty at the top with low humidity, but towards the bottom along the Colorado River, it is cooler because you are in the shade, but also humid due to the River itself.
That is what the people named it. They noticed the canyon as being rather large and bigger than any other canyon they had seen, so they named it the Grand Canyon.
No one knows for sure how long it has taken the Grand Canyon to form (est anywhere 5-17 million years) But the park itself was established in 1919. There are many canyons that the the Colorado River...
At one time there were mountains as tall as Mt Everest. The Geologists know this from the rocks the bottom of the canyon known as Vishnu Schist.The geologist learn about these rocks with new machines...