Clay should not be fired until it is bone-dry. To check for this, pick up your pot and feel it all over. If it feels cool to the touch, it is not yet bone-dry. (The coolness is due to the water evaporating out of the clay body.)
Drying time varies according to the humidity of the air. Generally, a pot should dry completely in one to two weeks. If a pot is drying faster than that, cover it lightly with plastic. Drying too fast can result in the pot cracking. Be aware that greenware is very fragile; dry your pots in a place where they won't be moved about, bumped or jostled.