The climate on Kauai varies depending on which part of the island you are on. It can be tropical or almost desert like. Some places are drenched with rain almost continuously. The tropical area makes a great place for a tropical botanic garden so that is exactly what is there. The garden is located inland from the entrance so you need to take a shuttle to get into it. Once there, you are free to wander around.
There are some really interesting plant types and the landscaping of the place is very attractive. There were a few other visitors when we were there but it certainly wasn’t busy and we could be pretty much alone as we wandered around. It did rain a little while we were there. This is supposed to be the drier side of the island but I guess we brought the rain with us from the north side of the island. However, the showers were only occasional and we had borrowed umbrellas from the office so we were fine.