Location and Size
Wyoming is bordered on the north by Montana, on the east by South Dakota and Nebraska, on the south by Colorado, on the southwest by Utah, and on the west by Idaho. It is the tenth largest state in the United States in total area, containing 97,818 square miles (253,348 km²) and is made up of 23 counties. From the north border to the south border it is 276 miles (444 km); and from the east to the west border is 375 miles (603 km).
Mountain Ranges
The Great Plains meet the Rocky Mountains in Wyoming. The state is a great plateau broken by a number of mountain ranges. Surface elevations range from the summit of Gannett Peak in the Wind River Mountain Range, at 13,804 feet (4,207 m), to the Belle Fourche River Valley in the state’s northeast corner, at 3,125 feet (952 m). In the northwest are the Absaroka, Owl Creek, Gros Ventre, Wind River and the Teton ranges. In the north central are the Big Horn Mountains; in the northeast, the Black Hills; and in the southern region the Laramie, Snowy and Sierra Madre ranges.
The Snowy Range in the south central part of the state is an extension of the Colorado Rockies in both geology and appearance. The Wind River Range in the west central part of the state is remote and includes more than 40 mountain peaks in excess of 13,000 ft. tall in addition to Gannett Peak, the highest peak in the state. The Big Horn Mountains in the north central portion are somewhat isolated from the bulk of the Rocky Mountains.
The Teton Range in the northwest extends for 50 miles (80 km) and represents the most impressive section of mountains in the state. It is home to Grand Teton, the second highest peak in Wyoming, and to Grand Teton National Park, which preserves the most scenic section of the Teton range.
The Continental Divide spans north-south across the central portion of the state. Rivers east of the Divide drain into the Missouri River Basin and eventually the Atlantic Ocean. They are the Platte, Wind, Big Horn and the Yellowstone rivers. The Snake River in northwest Wyoming eventually drains into the Columbia River and the Pacific Ocean, as does the Green River through the Colorado River Basin.
The Continental Divide forks in the south central part of the state in an area known as the Great Divide Basin where the waters that flow or precipitate into this area remain there and cannot flow to any ocean. Instead, because of the overall aridity of Wyoming, water in the Great Divide Basin simply sinks into the soil or evaporates.
Several rivers begin or flow through the state, including the Yellowstone River, Powder River, Green River, and the Snake River.
Public Lands
Over 48% of the land in Wyoming is owned by the U.S. Government, which ranks 5th in the US in both total acres owned by the Federal Government and by percentage of a state's land owned by the Federal government. This amounts to about 30,099,430 acres owned and managed by the U.S. Government. The state government owns an additional 6% of all Wyoming lands, or another 3,864,800 acres.
The vast majority of this government land is managed by the the Bureau of Land Management and U.S. Forest Service in numerous National Forests, a National Grassland, and a number of vast swaths of public land.
In addition , Wyoming contains a number of specific areas that are under the management of the National Park Service and other agencies. They include:
Parks
Recreation Areas
National Monuments
National Historic Trails and Sites
National Parkways
Wildlife Refuges and Hatcheries
Climate
The climate in Wyoming is generally a semi-arid continental climate which is drier and windier in comparison to most of the United States with temperature extremes. Much of this is due to the topography of the state. Summers in Wyoming are warm with July high temperatures averaging between 85 °F (29°C) and 95 °F (35°C) in most of the state. With increasing elevation, however, this average drops rapidly with locations above 9,000 feet (2,743 m) averaging around 70 °F (21°C). Summer nights throughout the state are characterized by a rapid cooldown with even the hottest locations averaging in the 50-60 °F (10-14°C) range at night. In most of the state, the late spring and early summer is when most of the precipitation tends to fall. Winters are cold, but are variable with periods of sometimes extreme cold interspersed between generally mild periods, with Chinook winds providing unusually warm temperatures in some locations. Wyoming is an arid state with much of the land receiving less than 10 inches (25 cm) of rainfall per year. Precipitation depends on elevation with lower areas in the Big Horn Basin averaging 5-8 inches (125 - 200 mm) (making the area nearly a true desert). The lower areas in the North and on the eastern plains typically average around 10-12 inches (250-300 mm), making the climate there semi-arid. Some mountain areas do receive a good amount of precipitation, 20 inches (510 mm) or more, much of it as snow, sometimes 200 inches (510 cm) or more annually.
The climate of any area in Wyoming is largely determined by its latitude, altitude and local topography. When put together, these factors have a lot to do with airflow patterns, temperature variations, precipitation and humidity brought in by the weather systems that migrate eastward. In winter, Wyoming is often beneath the jet stream, or north of it, which accounts for its frequent strong winds, blasts of Arctic air and precipitation, all the necessary ingredients for great snow conditions at Wyoming's northwestern ski areas. In summer, the jet stream retreats northward to somewhere over Canada, leaving the state's weather mild and pleasant at a time when the majority of Wyoming's visitors choose to arrive. Jackson, located at 6,230 feet (1,899 m) above sea level and surrounded by mountains, can expect a high temperature in July of 80˚ F (26.6°C). The average is more likely to be 65˚ F (18.3°C). The closest National Weather Station (in Riverton on the other side of the Wind River Mountains at 4,955 feet (1,510 m)) reports slightly warmer July weather.
Weather and topography in Wyoming
both have more contrast than in most
other states. Severe weather is not
uncommon in Wyoming, with the state
being one of the leading states for
hail damage in
the United States. The number of
thunderstorm
days vary across the state with the
southeastern plains of the state
having the most days of thunderstorm
activity. Thunderstorm activity in
the state is highest during the late
spring and early summer. The
southeastern corner of the state is
the most vulnerable part of the
state to tornado
activity. Moving away from that
point and westwards, the incidence
of tornadoes drops dramatically with
the west part of the state showing
little vulnerability. Tornadoes,
where they occur, tend to be small
and brief, unlike some of those
which occur a little further east.