Texas is the second-largest state in the United States, with a total land area of 261,914 square miles. Its size and geographical location combine to give it a diverse climate, with a wide variety of local and regional climatic influences. Before discussing the historical record of past climate change in Texas and possible future changes as a result of global warming and other factors, this chapter will give an overview of Texas climate and how the climate is determined by topographic and other characteristics. Copyright 2011 by the University of Texas Press. All rights reserved.