Climate and monthly weather forecast
Montana, USA

Flag of Montana, USA
Flag of Montana, USA

The climate of Montana

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.

Weather hazards

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. Weather in January »

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. Weather in February »

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" (640mm) and south-central locations, such as Mystic Lodge with 29.8" (757mm), receive a large amount of snow along with the Beartooth Mountains. Rainfall is in small amounts with the west part of Montana receiving more than the east. Weather in March »

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" (38mm) to 2.5" (64mm), while the eastern part accumulates approximately 1" (25mm). 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. Weather in April »

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" (64mm) to 3" (76mm) 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 May »

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). Weather in June »

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" (25mm) to 2" (51mm) range. Weather in July »

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. Weather in August »

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" (25mm) to 1.5" (38mm). 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. Weather in September »

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. Weather in October »

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. Weather in November »

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. Weather in December »

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