Climate and monthly weather forecast
Boulder, MT

Weather in January

January, like December, is another subzero cold winter month in Boulder, Montana, with temperature in the range of an average low of 14.5°F (-9.7°C) and an average high of 29.7°F (-1.3°C). In January, the average high-temperature is practically the same as in December - a still freezing cold 29.7°F (-1.3°C). Weather in January »

Weather in February

The last month of the winter, February, is another freezing cold month in Boulder, Montana, with an average temperature varying between 29.3°F (-1.5°C) and 13.5°F (-10.3°C). In Boulder, the average high-temperature in February is almost the same as in January - a still freezing cold 29.3°F (-1.5°C). Weather in February »

Weather in March

March, the first month of the spring in Boulder, is a cold month, with an average temperature ranging between max 38.7°F (3.7°C) and min 21.6°F (-5.8°C). In Boulder, the average high-temperature in March increases from a freezing cold 29.3°F (-1.5°C) in February to a cold 38.7°F (3.7°C). Weather in March »

Weather in April

April is a frosty spring month in Boulder, Montana, with an average temperature ranging between min 27°F (-2.8°C) and max 46.4°F (8°C). In April, the average high-temperature slightly increases from a wintry 38.7°F (3.7°C) in March to a frosty 46.4°F (8°C). Weather in April »

Weather in May

The last month of the spring, May, is a moderate month in Boulder, Montana, with an average temperature varying between 35.2°F (1.8°C) and 58.5°F (14.7°C). In Boulder, the average high-temperature in May increases from a chilly 46.4°F (8°C) in April to a moderate 58.5°F (14.7°C). Weather in May »

Weather in June

June, the first month of the summer in Boulder, is a pleasant month, with temperature in the range of an average low of 42.4°F (5.8°C) and an average high of 68.5°F (20.3°C). In June, the average high-temperature rises from a mild 58.5°F (14.7°C) in May to a pleasant 68.5°F (20.3°C). Weather in June »

Weather in July

July is a warm summer month in Boulder, Montana, with an average temperature varying between 48.4°F (9.1°C) and 79.7°F (26.5°C). The warmest month is July, with an average high-temperature of 79.7°F (26.5°C) and an average low-temperature of 48.4°F (9.1°C). Weather in July »

Weather in August

The last month of the summer, August, is also a moderately hot month in Boulder, Montana, with an average temperature fluctuating between 77.5°F (25.3°C) and 48.6°F (9.2°C). In Boulder, the average high-temperature in August is essentially the same as in July - a still warm 77.5°F (25.3°C). Weather in August »

Weather in September

The first month of the autumn, September, is still a comfortable month in Boulder, Montana, with an average temperature varying between 42.4°F (5.8°C) and 67.5°F (19.7°C). In September, the average high-temperature decreases from a warm 77.5°F (25.3°C) in August to an enjoyable 67.5°F (19.7°C). Weather in September »

Weather in October

October, like September, in Boulder, Montana, is another fresh autumn month, with temperature in the range of an average low of 31.3°F (-0.4°C) and an average high of 50.9°F (10.5°C). In Boulder, Montana, the average high-temperature in October plummets from an enjoyable 67.5°F (19.7°C) in September to a cool 50.9°F (10.5°C). Weather in October »

Weather in November

The last month of the autumn, November, is also a wintry month in Boulder, Montana, with temperature in the range of an average low of 21.2°F (-6°C) and an average high of 36.9°F (2.7°C). In November, the average high-temperature decreases from a cool 50.9°F (10.5°C) in October to a wintry 36.9°F (2.7°C). Weather in November »

Weather in December

The first month of the winter, December, is also a subzero cold month in Boulder, Montana, with an average temperature ranging between max 27°F (-2.8°C) and min 12.6°F (-10.8°C). December is the coldest month, with an average high-temperature of 27°F (-2.8°C) and an average low-temperature of 12.6°F (-10.8°C). Weather in December »
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FAQ

What is the most humid month in Boulder?

January is the most humid month in Boulder, Montana, with an average relative humidity of 86%.

How much does it rain in Boulder?

Throughout the year, in Boulder, there are 133.7 rainfall days, and 16.38" (416mm) of precipitation is accumulated.

When does it snow in Boulder?

January through June, September through December are months with snowfall in Boulder, Montana.

How many days does it snow in Boulder?

In Boulder, Montana, during the entire year, snow falls for 105.8 days and aggregates up to 55.12" (1400mm) of snow.

What is the month with the least sunshine in Boulder?

January and December, with an average of 5.6h of sunshine, are months with the least sunshine.

When does it snow the most in Boulder?

February is the month with the most snowfall in Boulder. Snow falls for 18 days and accumulates 9.72" (247mm) of snow.

What is the month with the lowest UV index in Boulder?

February is the month with the lowest UV index, with an average maximum UV index of 1.

When is Daylight Saving Time (DST) in Boulder?

On Sunday, March 13. 2022, at 2:00 am, Daylight Saving Time starts in Boulder, and the time zone changes from MST to MDT. Daylight Saving Time ends Sunday, November 6. 2022, at 2:00 am, and the time zone reverts from MDT to MST.

What is the wettest month in Boulder?

June is the month with the most rainfall. Rain falls for 16 days and accumulates 2.68" (68mm) of precipitation.

When are the longest days in Boulder?

The month with the longest days in Boulder is June, with an average of 15h and 43min of daylight.

What is the warmest month in Boulder?

The warmest month is July, with an average high-temperature of 79.7°F (26.5°C) and an average low-temperature of 48.4°F (9.1°C).

When it does not snow in Boulder?

In Boulder, Montana, snow does not fall in July and August.

What month has the most sunshine in Boulder?

With an average of 11.7h of sunshine, July has the most sunshine of the year in Boulder, Montana.

When is the highest UV index in Boulder?

July is the month with the highest UV index in Boulder, Montana, with an average maximum UV index of 6.

What is the least humid month in Boulder?

August is the least humid month, with an average relative humidity of 46%.

What is the coldest month in Boulder?

December is the coldest month, with an average high-temperature of 27°F (-2.8°C) and an average low-temperature of 12.6°F (-10.8°C).

What is the driest month in Boulder?

The month with the least rainfall is December, when the rain falls for 8.2 days and typically collects 0.79" (20mm) of precipitation.

What is the month with the shortest days in Boulder?

December has the shortest days of the year in Boulder, Montana, with an average of 8h and 41min of daylight.

Average temperature
Boulder, MT

Average temperature - Boulder, MT

The warmest month (with the highest average high temperature) is July (79.7°F).
The month with the lowest average high temperature is December (27°F).

The month with the highest average low temperature is August (48.6°F).
The coldest month (with the lowest average low temperature) is December (12.6°F).

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Average pressure
Boulder, MT

Average pressure - Boulder, MT

The month with the highest atmospheric pressure is January (30.19"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

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Average wind speed
Boulder, MT

Average wind speed - Boulder, MT

The windiest months (with the highest average wind speed) are January and November (6.5mph).
The calmest month (with the lowest average wind speed) is August (4.7mph).

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Average rainfall
Boulder, MT

Average rainfall - Boulder, MT

The wettest month (with the highest rainfall) is June (2.68").
The driest month (with the least rainfall) is December (0.79").

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Average rainfall days
Boulder, MT

Average rainfall days - Boulder, MT

The month with the highest number of rainy days is May (18.2 days).
The month with the least rainy days is November (7.5 days).

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Average snowfall
Boulder, MT

Average snowfall - Boulder, MT

The month with the highest snowfall is February (9.72").
The months with the least snowfall are July and August (0").

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Average snowfall days
Boulder, MT

Average snowfall days - Boulder, MT

The month with the highest number of snowfall days is February (18 days).
The months with the least snowfall days are July and August (0 days).

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Average daylight / Average sunshine
Boulder, MT

Average daylight / Average sunshine - Boulder, MT

The month with the longest days is June (Average daylight: 15h and 43min).
The month with the shortest days is December (Average daylight: 8h and 41min).

The month with the most sunshine is July (Average sunshine: 11h and 42min).
The months with the least sunshine are January and December (Average sunshine: 5h and 36min).

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Average sunshine days
Boulder, MT

Average sunshine days - Boulder, MT

The month with the most sunshine days is September (17.9 days).
The month with the least sunshine days is February (8.5 days).

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Average visibility
Boulder, MT

Average visibility - Boulder, MT

The months with the highest visibility are April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January, February, March and December (5mi).

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