The Sahara (the world's largest and hottest desert, with temperatures reaching 57.6Â°C (136Â°F) and the Atacama (the world's driest desert) on the coast of Chile and the Kalahari in Africa were formed in this way.The Gobi Desert is a cold winter desert and daytime temperatures can drop to -30Â°C (22Â°F).he Sahara (the world's largest and hottest desert, with temperatures reaching 57.6Â°C (136Â°F) and the Atacama (the world's driest desert) on the coast of Chile and the Kalahari in Africa were formed in this way.