Phoenix is the largest and most populous city in the state of Arizona. It is also the state capital and the largest state capital in the United States in terms of population. Phoenix is the only state capital with a population of more than a million people. It is also the county seat of Maricopa County.It is the largest city in the Mountain Time Zone as well as the second largest city in the Western United States after Los Angeles, California. It is the region 's primary cultural, economic, and financial center. It is also major national transportation hub. Phoenix is located on the banks of what is now the normally dry Salt River (with the exception of Tempe Town Lake). The city was incorporated on February 25, 1881. The city 's metropolitan area is also known by its nickname, "The Valley of the Sun" or the shortened "The Valley," because the city is surrounded by mountains on all sides. Residents of the city are known as Phoenicians.The city is currently the fifth largest city in the United States in terms of population with a 2007 estimated population of 1,552,259. Its city proper is the tenth largest for land area in the United States at 517 square miles. Phoenix has an arid climate, with very hot summers and temperate winters. The average summer high temperature is among the hottest of any populated area in the United States and approaches those of cities such as Riyadh and Baghdad. The temperature reaches or exceeds 100 °F (38 °C) on an average of 89 days during the year, including most days from early June through early September. On June 26, 1990, the temperature reached an all-time recorded high of 122°F (50°C). Overnight lows greater than 80 °F (27 °C) occur frequently each summer, with the average July low being 83 °F (28 °C) and the average August low being 82 °F (28 °C). The all-time highest low temperature ever recorded was 96°F (36°C), which occurred on July 15, 2003. http://wikitravel.org/en/Phoenix