The freeze/thaw weather cycle that many parts of the country experiences is a key contributing factor to the formation of potholes. The more freeze/thaw cycles a pothole endures, the larger the pothole can become.
While potholes are typically associated with cold climates, drivers in warm climates also have to deal with these roadway nuisances. In these areas of the country, heat is the cause of the problem. Heat causes cracks in the pavement which gives water an entry point. As traffic goes over the gap that is formed in the pavement, the top layer of the pavement crumbles and collapses to form a pothole.