Monthly weather forecast and climate
Roundup, MT

Weather in January

January, the same as December, in Roundup, Montana, is a freezing cold winter month, with average temperature ranging between min 18.5°F (-7.5°C) and max 31.8°F (-0.1°C). In Roundup, Montana, the average high-temperature is relatively the same as in December - a still freezing cold 31.8°F (-0.1°C). Weather in January »

Weather in February

February, the last month of the winter, in Roundup, is a cold month, with average temperature fluctuating between 32.5°F (0.3°C) and 18°F (-7.8°C). In Roundup, the average high-temperature in February is relatively the same as in January - a cold 32.5°F (0.3°C). Weather in February »

Weather in March

The first month of the spring, March, is a frosty month in Roundup, Montana, with temperature in the range of an average low of 29.3°F (-1.5°C) and an average high of 45°F (7.2°C). In March, the average high-temperature increases, from a wintry 32.5°F (0.3°C) in February, to a frosty 45°F (7.2°C). Weather in March »

Weather in April

April in Roundup, Montana, is a cool spring month, with average temperature varying between 36.3°F (2.4°C) and 53.8°F (12.1°C). In Roundup, the average high-temperature in April marginally rises, from a frosty 45°F (7.2°C) in March, to a fresh 53.8°F (12.1°C). Weather in April »

Weather in May

May, the last month of the spring, in Roundup, is a comfortable month, with average temperature fluctuating between 45.7°F (7.6°C) and 64.2°F (17.9°C). In May, the average high-temperature rises, from a cool 53.8°F (12.1°C) in April, to an enjoyable 64.2°F (17.9°C). Weather in May »

Weather in June

June, the first month of the summer, in Roundup, is a moderately hot month, with temperature in the range of an average low of 54.5°F (12.5°C) and an average high of 75.2°F (24°C). In June, the average high-temperature increases, from an enjoyable 64.2°F (17.9°C) in May, to a warm 75.2°F (24°C). Weather in June »

Weather in July

July, like June, in Roundup, Montana, is a moderately hot summer month, with average temperature varying between 84.7°F (29.3°C) and 62.4°F (16.9°C). With an average high-temperature of 84.7°F (29.3°C) and an average low-temperature of 62.4°F (16.9°C), July is the warmest month. The average heat index is calculated to 84.2°F (29°C). Weather in July »

Weather in August

The last month of the summer, August, is also a moderately hot month in Roundup, Montana, with average temperature fluctuating between 82.8°F (28.2°C) and 61.5°F (16.4°C). In August, the average high-temperature is almost the same as in July - a still moderately hot 82.8°F (28.2°C). Weather in August »

Weather in September

September, the first month of the autumn, in Roundup, is still a pleasant month, with average temperature varying between 53.2°F (11.8°C) and 72.7°F (22.6°C). In September, the average high-temperature decreases, from a moderately hot 82.8°F (28.2°C) in August, to an agreeable 72.7°F (22.6°C). Weather in September »

Weather in October

October, the same as September, in Roundup, Montana, is a moderate autumn month, with average temperature varying between 56.3°F (13.5°C) and 39.7°F (4.3°C). In Roundup, Montana, the average high-temperature plummets, from a pleasant 72.7°F (22.6°C) in September, to a mild 56.3°F (13.5°C). Weather in October »

Weather in November

The last month of the autumn, November, is also a frosty month in Roundup, Montana, with average temperature fluctuating between 28.8°F (-1.8°C) and 43.2°F (6.2°C). In Roundup, the average high-temperature decreases, from a moderate 56.3°F (13.5°C) in October, to a frosty 43.2°F (6.2°C). Weather in November »

Weather in December

December, the first month of the winter, in Roundup, is also a subzero cold month, with average temperature varying between 18.5°F (-7.5°C) and 31.1°F (-0.5°C). The coldest month is December, with an average high-temperature of 31.1°F (-0.5°C) and an average low-temperature of 18.5°F (-7.5°C). Weather in December »
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FAQ

What is the most humid month in Roundup?

January is the most humid month in Roundup, with an average relative humidity of 77%.

How much does it rain in Roundup?

In Roundup, during the entire year, the rain falls for 114.3 days and collects up to 12.13" (308mm) of precipitation.

What is the driest month in Roundup?

The month with the least rainfall is January when the rain falls for 5.6 days and typically collects 0.55" (14mm) of precipitation.

When does it snow in Roundup?

January through May, September through December are months with snowfall.

How much does it snow in Roundup?

In Roundup, during the entire year, snow falls for 53.5 days, and aggregates up to 18.58" (472mm) of snow.

When does it snow the most in Roundup?

February is the month with the most snowfall in Roundup. Snow falls for 11.1 days and accumulates 3.78" (96mm) of snow.

What is the month with the least sunshine in Roundup?

Months with the least sunshine in Roundup are February and December, with an average of 5.2h of sunshine.

What is the rainiest month in Roundup?

The month with the most rainfall is May when the rain falls for 15.6 days and typically aggregates up to 1.97" (50mm) of precipitation.

When it does not snow in Roundup?

June through August are months without snowfall in Roundup, Montana.

When are the longest days in Roundup?

June has the longest days of the year in Roundup, with an average of 15.8h of daylight.

What is the warmest month in Roundup?

The warmest month is July, with an average high-temperature of 84.7°F (29.3°C) and an average low-temperature of 62.4°F (16.9°C).

What month has the most sunshine in Roundup?

With an average of 11.8h of sunshine, July has the most sunshine of the year.

When is the highest UV index in Roundup?

With an average maximum UV index of 7, July is the month with the highest UV index in Roundup, Montana.

What is the least humid month in Roundup?

The least humid month in Roundup is August, with an average relative humidity of 39%.

What is the coldest month in Roundup?

With an average high-temperature of 31.1°F (-0.5°C) and an average low-temperature of 18.5°F (-7.5°C), December is the coldest month in Roundup, Montana.

What is the month with the shortest days in Roundup?

With an average of 8.7h of daylight, December has the shortest days of the year.

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

December is the month with the lowest UV index in Roundup, with an average maximum UV index of 1.

Average temperature
Roundup, MT

Average temperature - Roundup, MT

The warmest month (with the highest average high temperature) is July (84.7°F).
The month with the lowest average high temperature is December (31.1°F).

The month with the highest average low temperature is July (62.4°F).
The coldest month (with the lowest average low temperature) is February (18°F).

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Average pressure
Roundup, MT

Average pressure - Roundup, MT

The month with the highest atmospheric pressure is January (30.13").
The month with the lowest atmospheric pressure is June (29.85").

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Average wind speed
Roundup, MT

Average wind speed - Roundup, MT

The windiest month (with the highest average wind speed) is January (11.2mph).
The calmest months (with the lowest average wind speed) are July and August (8.5mph).

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Average rainfall
Roundup, MT

Average rainfall - Roundup, MT

The wettest month (with the highest rainfall) is May (1.97").
The driest month (with the least rainfall) is January (0.55").

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Average rainfall days
Roundup, MT

Average rainfall days - Roundup, MT

The month with the highest number of rainy days is May (15.6 days).
The month with the least rainy days is February (4.6 days).

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Average snowfall
Roundup, MT

Average snowfall - Roundup, MT

The month with the highest snowfall is February (3.78").
Months with the least snowfall are June, July and August (0").

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Average snowfall days
Roundup, MT

Average snowfall days - Roundup, MT

The month with the highest number of snowfall days is February (11.1 days).
Months with the least snowfall days are June, July and August (0 days).

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Average daylight / Average sunshine
Roundup, MT

Average daylight / Average sunshine - Roundup, MT

The month with the longest days is June (Average daylight: 15.8h).
The month with the shortest days is December (Average daylight: 8.7h).

The month with the most sunshine is July (Average sunshine: 11.8h).
Months with the least sunshine are February and December (Average sunshine: 5.2).

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Average sunshine days
Roundup, MT

Average sunshine days - Roundup, MT

The month with the most sunshine days is September (19.5 days).
The month with the least sunshine days is April (12.8 days).

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Average visibility
Roundup, MT

Average visibility - Roundup, MT

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

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