According to the dictionary, hike means “to take a long walk” and climb means “to move upward”. Unfortunately, the dictionary does not always give you enough information about how native speakers actually use a word.
When we are talking about people, we usually only use the verb climb when we use our hands (like Spiderman or Mission Impossible!). If you are talking about walking up a hill or mountain, then we use the verb hike.
It is not safe to climb mountains without a rope and harness.
The child was climbing all over the furniture. (using his hands)
I like to go hiking on the weekend.
We hiked up Mount Hood over the weekend. (even though it was a mountain, we did not use our hands)
However, when we are not talking about people, you must use climb.
The car slowly climbed the mountain road.
The plane climbed above the clouds.
