This article is about the state of Arizona.Arizona is in the Southwestern United States as one of the Four Corners states. Arizona is the sixth largest state by area, ranked after New Mexico and before Nevada. Of the state’s 113,998 square miles (295,000 km2), approximately 15% is privately owned. The remaining area is public forest and park land, state trust land and Native American reservations.
Like other states of the Southwest United States, Arizona has an abundance of mountains and plateaus. Despite the state’s aridity, 27% of Arizona is forest, a percentage comparable to modern-day France or Germany. The world’s largest stand of ponderosa pine trees is in Arizona.
The Mogollon Rim, a 1,998-foot (609 m) escarpment, cuts across the state’s central section and marks the southwestern edge of the Colorado Plateau. In 2002, this was an area of the Rodeo–Chediski Fire, the worst fire in state history.
Located in northern Arizona, the Grand Canyon is a colorful, deep, steep-sided gorge, carved by the Colorado River. The canyon is one of the seven natural wonders of the world and is largely contained in the Grand Canyon National Park—one of the first national parks in the United States. President Theodore Roosevelt was a major proponent of designating the Grand Canyon area as a National Park, often visiting to hunt mountain lion and enjoy the scenery. The canyon was created by the Colorado River cutting a channel over millions of years, and is about 277 miles (446 km) long, ranges in width from 4 to 18 miles (6 to 29 km) and attains a depth of more than 1 mile (1.6 km). Nearly two billion years of the Earth‘s history have been exposed as the Colorado River and its tributaries cut through layer after layer of sediment as the Colorado Plateau uplifted.
Arizona is home to one of the most well-preserved meteorite impact sites in the world. Created around 50,000 years ago, the Barringer Meteorite Crater (better known simply as “Meteor Crater“) is a gigantic hole in the middle of the high plains of the Colorado Plateau, about 25 miles (40 km) west of Winslow. A rim of smashed and jumbled boulders, some of them the size of small houses, rises 150 feet (46 m) above the level of the surrounding plain. The crater itself is nearly 1 mile (1.6 km) wide, and 570 feet (170 m) deep.
Arizona is one of two U.S. states that does not observe Daylight Saving Time (the other being Hawaii). The exception is within the large Navajo Nation (which observes Daylight Saving Time), in the state’s northeastern region.
Due to its large area and variations in elevation, the state has a wide variety of localized climate conditions. In the lower elevations, the climate is primarily desert, with mild winters and extremely hot summers. Typically, from late fall to early spring, the weather is mild, averaging a minimum of 60 °F (16 °C). November through February are the coldest months, with temperatures typically ranging from 40 to 75 °F (4 to 24 °C), with occasional frosts.
About midway through February, the temperatures start to rise, with warm days, and cool, breezy nights. The summer months of June through September bring a dry heat from 90 to 120 °F (32 to 49 °C), with occasional high temperatures exceeding 125 °F (52 °C) having been observed in the desert area. Arizona’s all-time record high is 128 °F (53 °C) recorded at Lake Havasu City on June 29, 1994, and July 5, 2007; the all-time record low of −40 °F (−40 °C) was recorded at Hawley Lake on January 7, 1971.
Due to the primarily dry climate, large diurnal temperature variations occur in less-developed areas of the desert above 2,500 ft (760 m). The swings can be as large as 83 °F (46 °C) in the summer months. In the state’s urban centers, the effects of local warming result in much higher measured night-time lows than in the recent past.
Arizona has an average annual rainfall of 12.7 in (323 mm), which comes during two rainy seasons, with cold fronts coming from the Pacific Ocean during the winter and a monsoon in the summer. The monsoon season occurs toward the end of summer. In July or August, the dewpoint rises dramatically for a brief period. During this time, the air contains large amounts of water vapor. Dewpoints as high as 81 °F (27 °C) have been recorded during the Phoenix monsoon season. This hot moisture brings lightning, thunderstorms, wind, and torrential, if usually brief, downpours. These downpours often cause flash floods, which can turn deadly. In an attempt to deter drivers from crossing flooding streams, the Arizona Legislature enacted the Stupid Motorist Law. It is rare for tornadoes or hurricanes to occur in Arizona.
Arizona’s northern third is a plateau at significantly higher altitudes than the lower desert, and has an appreciably cooler climate, with cold winters and mild summers, though the climate remains semiarid to arid. Extremely cold temperatures are not unknown; cold air systems from the northern states and Canada occasionally push into the state, bringing temperatures below 0 °F (−18 °C) to the state’s northern parts.
Indicative of the variation in climate, Arizona is the state which has both the metropolitan area with the most days over 100 °F (38 °C) (Phoenix), and the metropolitan area in the lower 48 states with the most days with a low temperature below freezing (Flagstaff).
Average daily maximum and minimum temperatures for selected cities in Arizona
Arizona remained sparsely settled for most of the 19th century. The 1860 census reported the population of “Arizona County” to be 6,482, of whom 4,040 were listed as “Indians”, 21 as “free colored”, and 2,421 as “white”. Arizona’s continued population growth puts an enormous stress on the state’s water supply. As of 2011, 61.3% of Arizona’s children under the age of 1 belonged to minority groups.
The population of metropolitan Phoenix increased by 45.3% from 1991 through 2001, helping to make Arizona the second fastest-growing state in the U.S. in the 1990s (the fastest was Nevada). As of July 2017, the population of the Phoenix area is estimated to be over 4.7 million.
According to the 2010 United States Census, Arizona had a population of 6,392,017. In 2010, illegal immigrants constituted an estimated 7.9% of the population. This was the second highest percentage of any state in the U.S.
Metropolitan Phoenix (4.7 million) and Tucson (1 million) are home to about five-sixths of Arizona’s people (as of the 2010 census). Metro Phoenix alone accounts for two-thirds of the state’s population.