| Arizona has three principal topographic areas, which | | | | and juniper trees. Most of Arizona lies in the drainage |
| control the Arizona heating and air climate. The | | | | basin of the Colorado River, which empties eventually |
| northeastern section of the state has a high plateau | | | | into the Gulf of California. The world-famous Grand |
| which averages 6,000 feet in elevation. There is a | | | | Canyon extends towards the southwest 217 miles |
| mountainous area which runs from southeast to | | | | from the confluence of the Little Colorado with the |
| northwest with between 9,000 and 12,000 feet | | | | main river. The width of the Grand Canyon varies |
| elevations. The southwestern part of the state | | | | from 4 to almost 18 miles, and its depth varies from |
| features desert valleys and low mountain ranges. An | | | | 2700 to 5700 feet. |
| unbroken forest of Ponderosa Pine lies between the | | | | Arizona heating and cooling in winter can result from |
| White Mountain region and the San Francisco | | | | masses of cold air which travel from Canada, bringing |
| Mountains, and this strip of forest continues north of | | | | with them below-zero temperatures in the |
| the Grand Canyon along the Kaibab Plateau and on | | | | mountainous and high plateau areas in the central and |
| into the southern part of Utah. The highest point in | | | | northern parts of the state. Low temperatures can |
| Arizona, with elevation 12,611 feet, is Humphreys | | | | reach 35° below zero Fahrenheit in the winter. In |
| Peak which is northwest of Flagstaff. The second | | | | the summer months at lower elevations |
| highest point is Baldy Peak, elevation 11,490 feet, | | | | temperatures exceeding 125° Fahrenheit have |
| located in eastern Arizona's White Mountains. On the | | | | been recorded. Moreover, there can be vast |
| other hand, the elevations of the desert Valleys in | | | | extremes between daytime and nighttime |
| the Lower Colorado River Valley in the southwestern | | | | temperatures exceeding 50° Fahrenheit in many |
| portion of the state are as low as 100 feet. | | | | parts of the state in the drier months of the year. In |
| Arizona heating and precipitation vary considerably as | | | | the winter the daytime temperature in the desert |
| a result of this topographic variation. In the higher | | | | valleys can average 70° Fahrenheit, with the |
| elevations, which run diagonally from the southeast | | | | nighttime temperature falling to below freezing. In the |
| of the state to the northwest, the rainfall averages | | | | summer in the pine clad forests in the central region |
| between 25" and 30" per year. On the other hand, | | | | of Arizona the daytime temperature may average |
| the desert regions in the southwest portions of the | | | | 80° Fahrenheit and then fall to 35° |
| state average as low as 3" to 4" per year. The | | | | Fahrenheit at night. As one might suppose, the length |
| northeastern plateau region receives about 10" of | | | | of the possible growing season can vary a great deal |
| precipitation per year. Because most of the | | | | in different parts of the state, averaging under three |
| vegetation in this region consists of native grasses | | | | months in the higher regions in the north and east |
| and sagebrush, the area is utilized mostly for grazing. | | | | whereas the lower desert valleys can go for years |
| The high ridges in this area are covered with pinion | | | | without a freeze. |