Montana has a northern Pacific coastal climate with cool summers and mild winters in the western part of the state, while the eastern part, separated by the Continental Divide, experiences a semi-arid, continental type of climate (Köppen climate classification BSk) with warm summers and cold winters. Wyoming in the south, Idaho in the west, the Canadian provinces of Alberta, British Columbia and Saskatchewan in the north, and North Dakota and South Dakota in the east, border the state. The climate varies considerably due to the variation in topography, geography, and altitude in different parts of the state.
Montana, the Big Sky Country, is home to many mountains - the western half contains numerous mountain ranges of the Rocky Mountains, while the eastern half mainly consists of the prairie landscape. The largest landlocked American state lies in the Western United States, and the Continental Divide splits the state into western and eastern regions, which have different climates. The Continental Divide creates two distinct climate types in the state as it prevents drier air from moving west and warmer air from the Pacific from moving east.
Altitudes vary from 600 meters to 4000 meters above sea level - additionally, the geography and topography lead to significant temperature variations. July has peak summer temperatures averaging 85°F (29.4°C), while January sees the lowest average temperatures of 0°F (-17.8°C). The record high temperature for the state is 117°F (47.2°C), set in Glendive on July 20, 1893, while the lowest record temperature is -70°F (-56.7°C), set in Rogers Pass on January 20, 1954 - the coldest ever in the United States. Summer days are moderate, while nights are cold and pleasant, and extreme temperatures are rare. Winters are cold as Montana lies between the 45th and 49th parallel, and cold air from Canada often causes a substantial drop in temperature within a brief period. Chinook winds from the southwest help to raise the temperatures in the warm 50°F (10°C) to 60°F (15.6°C) range, especially in the areas east of the mountains - there are instances where the winds changed the temperatures from -50°F (-45.6°C) to 49°F (9.4°C) within a day.
Montana averages an annual rainfall of 15" (381mm) with significant variations between the west and east as the high mountain ranges create rain shadow regions on the eastern side. The windward sides see 30" (762mm) of rain, while most of the leeward sides rarely go above 10" (254mm). Mountains themselves experience 100" (2540mm) of rain, while it is common for them to accumulate 300" (7620mm) of snow during the year. Many areas average between 30" (762mm) and 50" (1270mm) of snow, and it rarely relents barring the summer months.
The best time to visit Montana
Summers are pleasant with moderate temperatures - so the best time to visit Montana is during the summer to early fall, particularly from June to September. Spring is cold, while early summer is prone to rain and thunderstorms. The late part of autumn invites cold and windy conditions, so summer experiences the best weather. Summers tend to be moderate in the mountain ranges, but the lowlands see many days in the 75°F (23.9°C) to 85°F (29.4°C) range. Summer sees a vast rise in tourist numbers, especially in the Yellowstone and Glacier national parks, even though accommodation rates are at yearly highs.
The worst time to visit Montana
November to February is the worst time to visit Montana, as the state experience severe cold weather and extreme temperatures. Cold fronts are common during the winter that sees a substantial drop in temperatures. Mountain trails close during the winter due to intense cold as they gather vast amounts of snowfall often up to 300" (7620mm). Majority of the towns in the prairie register 30" (762mm) to 50" (1270mm) of snow during the winter. Winter days are rarely above freezing in many parts of Montana, and the Chinook winds provide some respite to the cold. Winter is a slow tourist season, which draws some visitors due to off-season discounts and winter activities.
Montana is prone to wildfires and thunderstorms in late spring and early summer. Hot and dry conditions that peak during the summer increase the frequency and intensity of wildfires in the forested areas of the state. Snowstorms are frequent during the winter, and blizzards deposit vast amounts of snow that stall towns and cities for days. Snowfall and bitter winter cold amplifies during the storms as the roads become impassable and the mountain trails almost unreachable.
Weather in January
January is the coldest month of the year in Montana as the temperatures are in the frigid zones. The average low temperatures in the eastern half dive to 2°F (-16.7°C) in Glasgow, while they are around 22°F (-5.6°C) in Flathead Lake in western Montana. Average high temperatures are in the 22°F (-5.6°C) to 32°F (0°C) zone as the days are short and cold in the absence of strong sun. January is also the snowiest month of the year that receives one-third of the average annual snowfall across the state. The southwestern mountain ranges receive a vast amount of snow to the tune of 40" (1016mm), while high elevation plateaus like Cooke City in the south accumulate 35" (889mm). January is a slow tourist season but sees winter enthusiasts for activities like dog sledding, sleigh riding, snowshoeing, and ice fishing, among others. Expect a deep snowpack in the mountains up to 100" (2540mm) and the sunshine to last only for 4 hours a day amid cloudy skies in the west and mostly clear skies in the east.
Weather in February
February is a cold winter month in Montana with the average temperatures in the cold 5°F (-15°C) to 40°F (4.4°C) zone across different regions of the state. The eastern portion of the state usually harbors cold air that is unable to pass to the west side most of the time due to the tall mountains of the Continental divide - sometimes the cold mass escapes through passes like Rogers Pass, Marias Pass, and other low elevation mountain passes and brings severe cold to northwest Montana's valley regions. Snowstorms and blizzards are frequent during the winter, and highways have snow fences in many places to shield from the snow. The weather is irregular with vast differences in temperatures - two places that lie near each other may even see a difference of 50 degrees when separated by a tall mountain. Cloud cover and wind speed increase in winter, while rain takes the form of ice and snow. Overall, expect snow and ice cover in most places with slanting sunrays and chilly weather.
Weather in March
March is a cold month that tails the winter season in Montana. Spring sees snowfall in most regions, with the valleys also receiving fair amounts of snow. Locations in the southwest such as Hebgen Lake Dam at 25.2" (640.1mm) and south-central locations, such as Mystic Lodge with 29.8" (756.9mm), receive a large amount of snow in March along with the Beartooth Mountains. Rainfall is in small amounts with the west part of Montana receiving more than the east. Roughly 10 to 12 days experience sunshine in March, and the conditions are windy and cold in most places. The average high temperatures are in the mild 40°F (4.4°C) to 50°F (10°C) range, while the nights are cold with average low temperatures in the frigid range of 15°F (-9.4°C) to 30°F (-1.1°C). Though the severe cold of winter subsides by early spring, it is still cold and windy with a little moisture in the air. Therefore, pack in layers for availing early-bird discounts during the spring season as the tourist season still lacks numbers.
Weather in April
April is a relatively wet month in Montana with mild days and cold nights. Spring advances everywhere and leaves the severe cold behind to the delight of the tourist population. Western Montana usually receives rain between 1.5" (38.1mm) to 2.5" (63.5mm), while the eastern part accumulates approximately 1" (25.4mm). Snowfall is still present in many places, but the amount generally limits to 5" (127mm) except in the high mountain ranges and plateaus where it registers high numbers. April sees comfortable day temperatures in the 50°F (10°C) to 60°F (15.6°C) range, while the night temperatures cross the freezing point. Sunlight improves to 60% as the days become longer, and the winter chill becomes rare. April in Montana sees an influx of tourists due to the rise in temperatures and the absence of extreme conditions - it also opens up the summer fishing season as the snow melts down; Montana allows hunting game with special permissions for which April is a good time at the end of the winter.
Weather in May
May is one of the beautiful times to visit Montana with comfortable weather as the spring blossoms in the state. Missoula in the northwest has average temperatures in the comfortable 40°F (4.4°C) to 67°F (19.4°C) range, while Helena, the capital of Montana in the southwest, averages a mild 41°F (5°C) to 67°F (19.4°C); much of the eastern part is warm with Glendive between 45°F (7.2°C) and 70°F (21.1°C) and Great Falls between 39°F (3.9°C) and 65°F (18.3°C). By May, snow restricts to the upper mountain ranges and highlands as rain replaces it and registers an average of 2.5" (63.5mm) to 3" (76.2mm) in many regions. The sunshine that was lacking in the early spring makes a comeback in the latter part of spring amid glorious days and cacophony of singing birds, animals, and tourists. Beware, while planning to visit Makoshika or Medicine Rock State Parks in the east as eastern Montana warms more and gets heavy rain as compared to the western part that sees mostly light but persistent rain.
Weather in June
June is one of the best times to visit Montana as the state basks in the glorious temperate sun. The average high temperatures are in the delightful 70°F (21.1°C) to 80°F (26.7°C) range, while average low temperatures are around a mild 40°F (4.4°C) to 55°F (12.8°C). Sunshine is plenty in the lower valleys, and the higher plains also receive adequate sunlight during the summer. June is wet in many places as the rain gauge accumulates 3" (76.2mm) with heavy showers, especially in eastern Montana. Summer conditions are pleasant in the fertile river valleys such as the Paradise Valley, Big Hole Valley, and Gallatin Valley, among many others. However, keep an eye on the weather for thunderstorms, which are common during the summer, and the vastly open plains provide a little respite from the storms and the rain! Carry rain protection and pack layered clothing, especially on the high mountain trails or the badlands. June sees a swarm of tourists in Montana, around the Glacier and Yellowstone national parks, and many other state parks.
Weather in July
July is the hottest month of the year in Montana with beautiful summer weather. The average high temperatures in the state are 75°F (23.9°C) to 88°F (31.1°C) and the night temperatures average 40°F (4.4°C) to 55°F (12.8°C). July is a little damp, but the rain is usually light and in the 1" (25.4mm) to 2" (50.8mm) range. Sunshine is the general norm everywhere, yet the temperatures are moderate, and it is rare for any place to see the mercury column touch 100°F (37.8°C). Thunderstorms sometimes happen in July, but they are mostly of the dry type and occur mainly in the eastern portion of Montana. Keep in mind, particularly in the highlands and mountain ranges, that temperatures plummet during the night, so keep warm clothes when camping in the mountains and national parks. Higher altitude valleys like the Big Hole River valley and West Yellowstone see freezing temperatures in the night even with high summer day temperatures!
Weather in August
August is a beautiful summer month in Montana as most of the state registers day temperatures in the 70°F (21.1°C) to 90°F (32.2°C). Summers are dry as the humidity hardly touches 45% in most of the state. August has an average of 24 sunny days in which the sunshine averages for 9 hours a day. West Glacier averages between 47°F (8.3°C) to 79°F (26.1°C) in the northwest, Butte 44°F (6.7°C) to 80°F (26.7°C) in the southwest, Bighorn Lake 56°F (13.3°C) to 88°F (31.1°C) in south-central, while Miles City in eastern Montana is the warmest with 58°F (14.4°C) to 87°F (30.6°C). Rainfall subsides by August and rarely goes over 1" (25.4mm) to 1.5" (38.1mm) in the majority of the state. While light clothing is usually sufficient during the days, the nights require layers due to the drop in temperatures. It is an excellent idea to carry an insect repellent during the dry summer, as insects are common in the prairie.
Weather in September
September transitions to the beautiful autumn season that has average high temperatures in the 60°F (15.6°C) to 70°F (21.1°C) range and the nights are relatively cooler in the average low temperature range of 35°F (1.7°C) to 45°F (7.2°C). Summer thunderstorms sometimes extend to the early fall season, but they are mostly dry as the average rainfall rarely moves the needle beyond 1" (25.4mm) to 1.5" (38.1mm). Sunshine is adequate as September has an average of 18 days of sunny weather. The aspens turn yellow by Mid September as the colorful fall season spreads its wings over Montana. The Bitterroot River displays beautiful fall colors, while nearby Hamilton has a variety of trees that display shades of orange, red, and yellow against the backdrop of the panoramic Bitterroot Mountains. Wildlife is active during the autumn, and it is an excellent idea at least to carry a bear spray as an encounter with a big one of the species is a shock but not entirely a surprise!
Weather in October
October has cooler temperatures and highlights brilliant fall colors in Montana as many trees like the western larch are in full glory. It is one of the best times to visit Montana with beautiful weather, refreshing nature, abundant wildlife, and the call of the fishing and hunting seasons. Average high temperatures are in the range of 55°F (12.8°C) to 60°F (15.6°C), while average low temperatures register around 25°F (-3.9°C) to 40°F (4.4°C) across the state. Rain is negligible, but snow is present in small quantities in most of the state. October is the perfect time to visit Glacier National Park after the wildfire season is over during the summer and the return of most of the tourists. Early October is usually elk spotting season, and it is common to view a group of 500 in the Slippery Ann Elk Viewing Area to the north of Missouri. Hats, gloves, and jackets are usually better to wear in fall than shorts and t-shirts of summer.
Weather in November
November is the end of the autumn in Montana that sees cold temperatures in the average range of 18°F (-7.8°C) to 48°F (8.9°C) in the state. November sees snowfall to the tune of 5" (127mm) to 10" (254mm) in many places in the state. Sunny days are rare in November as the daily sunshine reduces to 4 hours. West Glacier in the northwest is between 26°F (-3.3°C) to 37°F (2.8°C), while Glasgow in the east averages between 19°F (-7.2°C) to 40°F (4.4°C). Fall brings unpredictable weather that may show shades of sunny, cold, or snowy in different regions at the same time. Clear blue skies may succeed with thunderstorms, and the green grass of summer may combine with the bare branches of trees of winter. A great way to experience the fall colors is kayaking, canoeing, or boating on the countless rivers and lakes in the Glacier Country. Other ways to view the fall foliage are scenic roadways, biking, and trailing in the mountains. Fall is one of the best times to fish the rivers such as Blackfoot River and Flathead River in Western Montana.
Weather in December
December is severely cold in Montana with the average high temperatures in the 25°F (-3.9°C) to 32°F (0°C) range and the average low temperatures in the freezing -1°F (-18.3°C) to 21°F (-6.1°C) range. The eastern half of the state is prone to cold weather with average low temperatures of 7°F (-13.9°C) in Glasgow and 8°F (-13.3°C) in Havre City, while the western half is comparatively warm with average low temperatures of 16°F (-8.9°C) in Kalispell and 21°F (-6.1°C) in Libby. Snowfall is severe in the mountains and often crosses 50" (1270mm), while rain is mainly in the form of icy precipitation. The winter also brings a chilly wind that exacerbates the cooling effect, which the Chinook winds partially neutralize to keep the temperatures in check. The average monthly sunshine is in the range of 45% to 50%, which means short days with a weak presence of the sun. The intense cold mandates warm winter coats, caps, gloves, and boots during Christmas and New Year's Eve, whose celebrations mostly occur in the white blanket of snow!.