West Yellowstone Geography: Yellowstone Volcano, Caldera

Get an understanding of Montana’s unique geography so you can experience even more pleasure as you explore the mountains, lakes and rivers of this incredible Big Sky region.

Geography

Montana, in the western US, is our fourth largest state, with 145,552 square miles. Bordered by Idaho on the west, Wyoming on the south and North Dakota and South Dakota on the east, Montana shares a 545-mile border with Canada to the north. The three provinces of Canada sharing our Montana border are British Columbia, Alberta and Saskatchewan.

Climate

Montana has quite a varied climate, as elevations in the state range from under 2,000 feet to almost 13,000 feet above sea level.

Summer
There can be quite a variation in temperatures during the summer in Montana, but in general, the weather is wonderful throughout the state. The months of summer are dry for the most part, with a few days of clouds and light rains. You’ll find more thunderstorms occurring in the eastern half of Montana. It can snow in July or August in the higher elevations, but it’s rare to find it snowing at this time in the major cities.

In the western part of the state, temperatures range in the daytime from the mid-70s to about 90. This, of course, depends on the elevation. In the eastern part of the state, daytime highs will be in the 80s and 90s. Temperatures can soar to the 100s during heat waves, however, and this is a good time to “head for the hills.” You’ll find nighttime temperatures average from around the 40’s to lower 50’s.

Fall
Fall begins in Montana in late September and runs into the month of November, but temperatures start to cool off early in September. The days are still mostly dry and beautifully sunny. The weather can change rapidly during this time of year, and you can have a warm period of Indian summer followed by cold rain and even snow.

In Western Montana, the temperatures drop on occasion through October, until in November you are getting much colder weather with more rain and more cloud. East of the Continental Divide, you’ll have bigger temperature changes, until in October the cold arctic winds blow in from Canada.

Winter
There are some real extremes in temperatures in the winter months in Montana. Winter cold spells can last a week or two, but it’s known that Chinook winds can bring rapid increases in temperatures, jumping as much as 40 or 50 degrees within only a few minutes.

The average maximum daytime temperature in winter is around 27 degrees F. in Montana. At night, temperatures can drop to well below 0. The coldest temperature recorded in the state was in 1954 at a mining camp close to Rogers Pass, at –70 degrees F. The western part of the state is usually a lot warmer than the eastern section and the eastern part also receives more snowfall than the west.

Spring
Spring in Montana brings the rainy season. Snow can also fall, but as spring moves forward, the chances of snowfall are less and less. Rain is more common for the valleys while snow comes down in the mountainous areas.

Western Montana takes a long time to get warm after a long hard winter, with lots of clouds and cool temperatures and rain. The east tends to warm faster and sections can even get quite hot.

Terrain

Moving from west to east in Montana, you will see great changes in the geography of the land, with numerous mountain ranges, and this is where Montana gets its name. “Montana” is the Spanish word for “mountain.” The state is basically divided by the Continental Divide, which runs diagonally from northwest to the south central part of the state. The Bitterroot Mountains blend into the Continental Divide in the south.

The western third of Montana has many ranges, known as the Northern Rockies. West of the divide, you’ll find the Clark Fork of the Columbia, flowing northwest to Missoula and joining the Blackfoot and Bitterroot Rivers. In this region you’ll also find Flathead Lake, the largest natural fresh-water lake in the western United States.

While the eastern part of the state mostly consists of the grasslands of the northern Great Plains, there are still some mountain ranges with scenic valleys. In the center of the state you’ll find the Missouri River flowing into North Dakota. Some of the ranges in the southern half of Montana are the Gallatin Range and the Bridger, Absaroka and Beartooth Mountains.

The Yellowstone River begins its journey in Yellowstone Park, to the south in Wyoming, and travels north then east to Billings, Montana and carries on until it joins the Missouri. There are a number of man-made reservoirs throughout Montana, the best known being the Fort Peck Reservoir, where you can see the largest earthen dam in the world.

Population

Montana is 44th in population in the United States; so only six other states have less people. In 2009, Montana’s population was estimated at 974,989. The most populous areas are the cities of Billings, Missoula, Bozeman, Kalispell, Great Falls, Helena and Butte, in that order.