The Climate of Idaho

By | August 27, 2022

The US state of Idaho (ID) is located in the northwestern United States. Idaho has a primarily mountainous landscape. The Rocky Mountains determine a large part of the beautiful landscape, which sometimes has very rough sides, such as in the Hells Canyon and Balanced Rock. Idaho has a combination of arid and continental climates, with almost without exception warm summers and winter months that are cool, but locally barren and angry. This is especially noticeable in eastern Idaho, where the influence of the Pacific Ocean is clearly diminishing, making extreme cold significantly more likely to strike. In the mountains, night frost is still possible during the hottest summer months. This is how it is at the popular winter sports location Sun Valley(1,800 meters above sea level) during the night hours of freezing all year round, while the average maximum temperature in the hottest months of July and August is around 24/25 degrees Celsius.

Another characteristic of Idaho is that the annual amount of precipitation is quite low. On average, there is about 300 to 500 millimeters per month, with occasional peaks on the windward side of mountains. In the west, winters are wetter than summers, due to the supply of wet air from the Pacific Ocean. In the east there are more often slightly wetter summers. However, precipitation in winter often falls in the form of snow.

Climate figures

The figures below are based on long-term average climate statistics. The temperatures are displayed in degrees Celsius (°C).

maximum temperature minimum temperature hours of sunshine per day days of rainfall per month
January 2℃ -6℃ 4 12
February 7℃ -3℃ 5 9
March 12℃ -1℃ 8 10
April 16℃ 2℃ 9 9
May 22℃ 6℃ 11 7
June 27℃ 11℃ 12 6
July 32℃ 14℃ 13 3
August 31℃ 13℃ 12 4
September 25℃ 8℃ 10 5
October 18℃ 3℃ 8 6
November 10℃ -1℃ 4 11
December 2℃ -6℃ 3 12

The climate of Boise

Boise is the capital of the US state of Idaho. Boise is a fairly dull provincial town without any real tourist attractions. Worth seeing are the Idaho Capitol, the zoo and Julia Davis Park. About 25 kilometers away is the Bogus Basin, a popular recreational and winter sports area in the mountains at an altitude of 1675 to a maximum of 2311 meters above sea level. The ski season usually starts over the Thanksgiving weekend and lasts until the last weekend before April 15. Of course, the snow conditions determine the final length of the winter sports season.

Boise has a cold steppe climate thanks to the average annual precipitation of almost 300 millimeters. Within the Köppen climate classification, this is indicated by the code BSk. Winters are quite cool, gloomy and on the humid side. The summer months are warm, very sunny and dry. In the months of July and August there is hardly any rain, while the sun shines exuberantly. The month of July records no less than 400 hours of sunshine (long-term average), making this month an important share of the annual number of almost three thousand hours of sunshine.

The Climate of the City of Rocks National Reserve

The City of Rocks National Reserve is well known among rock climbers. Located in the US state of Idaho, this state park is known for its various rock formations. The rocks consist mainly of granite. The historic California Trail along which settlers moved west runs through the park. You can walk part of this trail. This way you can discover the names of the pioneers carved into the rocks. A large number of climbing routes run through the park, which can be simple at times, but also very challenging. Some rocks and rock formations are no longer allowed to be climbed, such as the well-known Twin Sisters. The reason is that climbing this important geological formation would disrupt the historic view of the California Trail.

Semi-arid climate

The City of Rocks National Reserve has a semi-arid climate, with winters being on the cool side and summers often warm to very hot. The average amount of precipitation that falls from the sky on an annual basis is between 250 and 300 millimeters. This is spread evenly over the calendar year. Those looking at the City of Rocks National Reserve’s climate statistics will see that May is fractionally wetter. In practice this is hardly noticeable. In winter, part of the precipitation falls in the form of snow instead of rain. The greatest chance of snowfall is from December to February.

Spring and fall are the best time to travel to the City of Rocks National Reserve. During these two seasons, the chance of afternoon temperatures of 30 degrees or higher is much smaller than during the hottest months (July and August). Then tropical temperatures are normal and you can even have to deal with thermometers that indicate values ​​well above 30 degrees.

The climate of Coeur d’Alene

Coeur d’Alene is a city located in the north of the US state of Idaho. The place is located on the north side of Lake Coeur d’Alene. This lake is widely used for recreational purposes such as boating, swimming and canoeing. Around the lake there are plenty of opportunities for walking and cycling. A special path is the Trail of the Coeur d’Alenes. This former section of railway has a length of 117 kilometers, is paved and car-free. It is widely used for cycling, hiking and skating. Coeur d’Alene is a fairly lively town where tourism has been an important source of income since the 1980s. In the winter you can enjoy winter sports in the vicinity, while in the summer months being active in the open air is especially popular.

Coeur d’Alene has a climate that can be seen as both a moderate Mediterranean climate (Csb climate) and a moderate continental climate (Dsb climate). Based on the precipitation criterion (< 30 millimeters in the driest month), we tend to refer to the moderate Mediterranean climate (Csb climate) in the case of Coeur d’Alene, with warm, dry summers and cool, wetter winters. On an annual basis, Coeur d’Alene receives about 650 millimeters of precipitation. The months of July, August and September are somewhat drier than the other months. In winter, snow regularly falls in the form of snow instead of rain.

In winter, temperatures in Coeur d’Alene are mainly around freezing, with an average of a few degrees above zero during the day and light frost at night. Periods of cold can occur, with severe freezing temperatures at night and well below zero during the day. Summers are a lot warmer in Coeur d’Alene. The maximum temperature in the hottest months (July and August) is around 28 degrees. During heat waves, the thermometers can soar well above 30 degrees.

The climate of the Craters of the Moon National Monument

It is a fact that planet Earth has many different landscapes. That some of those landscapes remind you more of a lunar landscape than our own planet is another fact. Volcanic landscapes in particular tend to look like they came from elsewhere. In colour, structure and vegetation (or lack thereof), these types of landscapes do not resemble what we think is normal. In the American state of Idaho, you can see the phenomenon of volcanic landscapes in the Craters of the Moon National Monument. The lava fields, lava monoliths and cone volcanoes give you the impression that you have landed somewhere on the Moon. Driving through the park via the only paved driving route, you will be treated to amazing facets of volcanic landscapes.

Within the Craters of the Moon National Monument, a semi-arid climate prevails. As a result, the chance that you will have to deal with rain or snow is quite limited. The annual precipitation sum remains on average slightly below 400 millimeters. In the period from November to mid-March there is a reasonable chance that the precipitation will have a winter character. On an annual basis there is an average of about 200 to 250 centimeters of snow. It can easily remain in place for longer periods in the fairly cool winters. In December and January night frost is almost certain and the average daytime mercury does not rise above freezing point. Summers are a lot warmer. During the hottest months (July and August) maximum temperatures are on average around 30 degrees. Every now and then you have a day or a few days where it gets a little warmer.

The climate of Idaho Falls

Idaho Falls is a large city in the eastern US state of Idaho. Idaho Falls is located in Bonneville County, on the Snake River. The city was founded in the second half of the 19th century but was then still called Eagle Rock. Several decades later, the name was changed to Idaho Falls after a referendum. In the city is the beautiful Idaho Falls Idaho Temple of the Church of Jesus Christ of Latter-day Saints (also known as Mormons).

Idaho Falls has a cold steppe climate, with little rainfall throughout the year. The winter period is long and there are long periods of frost and night frost. Summers are warm, with average temperatures around 30 degrees Celsius. During the hottest summer days, the sun shines for more than 12 hours a day. Precipitation will mainly come down as snow in the winter period.

The climate of Lewiston

Lewiston is a medium-sized city in northern Idaho, near the border with Washington. Lewiston is located in Nez Perce County, at the confluence of the Snake River and Clearwater River. The city was founded in the second half of the 19th century during the gold rush. Today, the city mainly lives from agriculture and logging. The Lewiston metropolitan area also includes parts of neighboring Washington state.

Lewiston has a cold steppe climate, with slightly higher precipitation figures than you would expect here. Winters are cool to cold, with a relatively short period of frost. The summers are long and very pleasant. On some days, the mercury can reach tropical temperatures. During the winter period, most precipitation will come down as snow.

The climate of McCall

McCall is a vacation town in western Idaho in the Payette National Forest. McCall is located in Valley County, on Lake Payette. Near the town itself is a small ski area (Little Ski Hill) that is provided by 1 lift. Because the track is lit, you can ski here at night. A little further from the village is the Tamarack Resort, with 39 ski runs and 5 lifts. In the summer months, most tourists stay here in and around the lake, where artificial beaches have been created in a number of places.

McCall has a moderate continental climate, with an icy cold winter and a short, mild summer. Most precipitation falls during the winter period and will mainly come down as snow during these months. Summers are short but pleasant, with average daytime temperatures just below 30 degrees Celsius.

The climate of Meridian

Meridian is a city in the southwest of the US state of Idaho. Meridian is the fastest growing city in the state and one of the fastest growing cities in the US. Meridian was founded in 1891 on Onweiler Farm north of its current location and was then called Hunter. In the first decades Meridian consisted mainly of farms. Settlers established fruit orchards where mainly apples and plums were grown. When that was no longer profitable, people mainly switched to dairy farming. The local milk factory closed its doors in 1970. Today Meridian has a broad economic base, with agriculture, light industry and high-tech industry as important pillars. The key to Meridian’s success is above all its excellent livability.

Meridian has a semi-arid climate, which has four distinct seasons. These seasons are mainly recognizable by the temperatures and the growing season in which the fauna is located. Winter is on the cool side with some snowfall. Not large amounts, because in general there is not much precipitation in Meridian. On an annual basis you should think of an average amount of less than 300 millimeters. Spring offers fertile weather, with quite large contrasts between the minimum and maximum temperatures. This is followed by a warm, dry summer. Afternoon temperatures of 30 to 35 degrees are very normal. Sometimes it can get blistering hot, with temperatures approaching 40 degrees. Autumn is quite dry with a steady drop in temperature.

The climate of Nampas

The city of Nampa is located in the southwest of the US state of Idaho. This, along with cities such as Boise and Meridian, makes up the Boise City–Nampa, Idaho Metropolitan Statistical Area. This is a metropolitan area where there is ample space between the different cities that make up it. One reason that there is such a high concentration of habitation here is that it is fairly flat and the climate is quite favorable for living. Nampa has no fewer than 24 parks, of which Lakeview Park is the largest. A beautiful nature reserve just outside the built-up area is formed by Lake Powell. The land surrounding this lake is an important breeding area for all kinds of mammals, birds and other animals. This area forms the Deer Flat National Wildlife Refuge.

Semi-arid climate

Nampa has a semi-arid climate, which has 4 seasons. Summers are dry and warm, with sometimes very hot weather for a few days. The winters are on average a bit on the cold side, with the occasional period when temperatures fall well below the long-term averages. In that case, severe to very severe frost can occur at night and the mercury often remains below freezing during the day. This especially happens when there is a so-called cold pit. Then very cool air descends from the polar region to the US and causes considerable cold, especially in the interior.

On an annual basis, Nampa receives only about 280 to 300 millimeters of precipitation. This is fairly evenly distributed over the year, although the summer months of July and August are slightly drier. Those are almost perfect summer months, with little rain and fairly high temperatures. The average maximum is then just above 30 degrees. In winter, precipitation often falls in the form of snow instead of rain. This mainly happens in the months of December, January and February. A flake of snow can still fall in March and even April, but the chance of that is considerably smaller.

The climate of Pocatello

Pocatello is a large city in the southeastern US state of Idaho. Pocatello is located in Bannock County, on the Portneuf River. Pocatello was an important stop on the railroad when the gold rush was at its peak here. Just outside the city is the Fort Hall Indian Reservation. This reserve is very popular here because of its casinos. Idaho State University is located in the city.

Pocatello has a cold steppe climate, which is characterized by low rainfall throughout the year. The winter months are quite cold, with long periods of frost and night frost. During the winter months, most of the precipitation here will come down as snow. Summers are short but warm, with the mercury regularly exceeding 30 degrees Celsius.

The climate of Sandpoint

Sandpoint is a town located fairly north in the US state of Idaho. Sandpoint is located in the Rocky Mountains, just 645 meters above sea level. The low location is because Sandpoint is located on Lake Pend Oreille, the largest lake in all of Idaho. Sandpoint is surrounded by three mountain ranges: the Selkirk, Cabinet and Bitterroot. The Schweizer Mountain Resort is a popular winter sports area about 20 kilometers from Sandpoint. With a base altitude of 1207 meters, a top altitude of 1951 meters and no less than 95 kilometers of slopes, this is a great place for skiing or snowboarding in the winter. This is often possible from the end of November. The ski season usually ends in early April. In the summer months, Sandpoint is certainly just as interesting. You can then recreate on or at the lake, the local ‘farmers markets’

Sandpoint has a moderate continental climate. Within the Köppen-Geiger climate system, this is a Dsb climate. The winters are cold and snowy, the summers dry and warm. Striking are the large daily temperature fluctuations that you will have to deal with during every season. For example, you can have warm weather during the day with an afternoon temperature of 30 degrees, after which the mercury drops to just above freezing at night when the sky is clear. The average maximum temperatures in the hottest months are around thirty degrees. In winter the maxima are around or slightly above freezing point, while at night it often freezes moderately (-5 to -10 degrees). During periods of cold it can freeze very severely in Sandpoint.

On an annual basis, there is an average of more than 800 millimeters of precipitation. That is an amount that is reasonably comparable to what we are used to in the Netherlands. What is an essential difference is that in Sandpoint the chance of precipitation is greater in winter. Then it mainly falls in the form of snow. On average, Sandpoint receives about one and a half to two meters of snow per year. In the higher ski resorts it is easy to double or even more.

The climate of Sun Valley

Sun Valley is a small town in the central part of the state of Idaho, in Blaine County. The village is best known for its ski areas. The Bald Mountain has 75 ski runs and is served by 14 ski lifts. The Dollar Mountain is especially popular with the novice skier because of its flat descent and relatively short slopes. The ski area here is served by 4 ski lifts. Often affectionately referred to as Baldy, Bald Mountain is very popular with alpine skiers. The Sawtooth National Recreation Area is located a few miles outside of town.

Sun Valley has a temperate continental climate, with cold winter months and warm summer months. Most precipitation falls during the winter period and will mainly consist of snow. The winter period mainly consists of long periods of frost and night frost. The summer period is short, with cold nights. Even in the summer months, periods of night frost can occur here.

The climate of Twin Falls

Twin Falls is a large city in the southern US state of Idaho. The city is located in Twin Falls County, on the Snake River, not far from Snake River Canyon. The first permanent residence here took place in the second half of the 19th century. Before this time, several Indian tribes lived in the region. The remains that have been found are among the oldest dated in the United States. In the Snake River are the Shoshone Falls, which are fourteen meters higher than Niagara Falls.

Twin Falls has a cold steppe climate, with about 250mm of annual precipitation, just a little too much for the cold desert climate. The winter months are cold, with long periods of frost and night frost. The low precipitation will mainly come down as snow during these months. Summers are particularly warm, with temperatures averaging above 30 degrees Celsius.

Twin Falls Idaho