Sorry, I'll rephrase.
Now, as you might now, there's a natural humidity in the air. Some air is dryer than other. Depending on that is the quantity of suiton chakra we liberate through the Kirigakure no jutsu. Now, being this a training ground the humidity of the air is avarage, needing an amount of suiton chakra to be infused with it and later manipulated. What I'm trying to say is that, you release your suiton chakra in such way you generate moisture in the air. In order to do so you can, apart from generating it from your chakra, infuse the chakra with the air so that you can augment the humidity (moisture is the more appropiate word) and thus creat a cloud at the grounds level also called, Mist.