September weather forecast
Bozeman, MT

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A sunny autumn morning in Bozeman, Montana
A sunny autumn morning in Bozeman, Montana

Weather in September

As September rolls in, Bozeman, Montana starts to transition from summer to the cooler autumn season. With lower average temperatures than August, the month also heralds the beginning of fall foliage. While the rainfall figures increment slightly from August, the weather remains pleasant enough for outdoor activities. The changing colors of the town's foliage against crisply blue skies manifest into a picturesque setting that illuminates September in Bozeman.

Temperature

A shift in the average high-temperature occurs in September, reducing from a moderately hot 75.6°F (24.2°C) in August to a comfortable 65.3°F (18.5°C). Despite a noticeable differential from daytime highs, Bozeman notes an average nighttime low-temperature of 40.5°F (4.7°C) in September.

Humidity

In September, the average relative humidity is 56%.

Rainfall

In Bozeman, in September, during 11.2 rainfall days, 1.81" (46mm) of precipitation is typically accumulated. Throughout the year, there are 131 rainfall days, and 23.15" (588mm) of precipitation is accumulated.

Snowfall

January through June, September through December are months with snowfall. September is the first month it typically snows. Throughout September, in the average 1.5 snowfall days, it receives 2.05" (52mm) of snow. Throughout the year, in Bozeman, there are 122.8 snowfall days, and 91.1" (2314mm) of snow is accumulated.

Daylight

In September, the average length of the day is 12h and 31min.
On the first day of the month, sunrise is at 6:46 am and sunset at 8:01 pm. On the last day of September, sunrise is at 7:22 am and sunset at 7:05 pm MDT.

Sunshine

In Bozeman, the average sunshine in September is 9.6h.

UV index

In September, the average daily maximum UV index is 3. A UV Index reading of 3 to 5 represents a medium health hazard from unprotected exposure to Sun's UV rays for average individuals.
Note: The maximum UV index, 3 during September, leads to the following recommendations:
Take heed. Individuals of lighter complexion can be burned in less than half an hour. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. For minimizing sun-related eye damage, always choose sunglasses with UVA and UVB coverage. Take note! UV radiation from the Sun can double in intensity due to snow reflection.
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Frequently asked questions

What is the average September temperature in Bozeman?

The average high-temperature and low-temperature in Bozeman, Montana, during September are 65.3°F (18.5°C) and 40.5°F (4.7°C) respectively.

What is the average humidity in September in Bozeman?

In Bozeman, Montana, the average relative humidity in September is 56%.

How many days does it rain in September in Bozeman?

In September, in Bozeman, Montana, the rain falls for 11.2 days. Throughout September, 1.81" (46mm) of precipitation is accumulated.

When does it start snowing in Bozeman?

September is the first month it typically snows in Bozeman, Montana. Throughout September, in the average 1.5 snowfall days, it receives 2.05" (52mm) of snow.

How many hours of daylight does Bozeman have in September?

The average day length in September in Bozeman, Montana, is 12h and 31min.

When are sunrise and sunset in September in Bozeman?

In September, on the first day of the month, sunrise is at 6:46 am and sunset at 8:01 pm. On the last day of the month, in Bozeman, Montana, sunrise is at 7:22 am and sunset at 7:05 pm MDT.

How many hours of sunshine does Bozeman have in September?

The average sunshine duration in September in Bozeman is 9.6h.

What is the UV index intensity in September in Bozeman?

The average daily maximum UV index in September in Bozeman is 3. A UV Index estimate of 3 to 5 represents a medium hazard to health from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Bozeman, MT

Average temperature in September - Bozeman, MT
  • Average high temperature in September: 65.3°F

The warmest month (with the highest average high temperature) is July (77°F).
The month with the lowest average high temperature is December (24.8°F).

  • Average low temperature in September: 40.5°F

The months with the highest average low temperature are July and August (46.9°F).
The coldest month (with the lowest average low temperature) is December (10.4°F).

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Average pressure in September
Bozeman, MT

Average pressure in September - Bozeman, MT
  • Average pressure in September: 29.98"Hg

The months with the highest atmospheric pressure are January and December (30.19"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).

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Average wind speed in September
Bozeman, MT

Average wind speed in September - Bozeman, MT
  • Average wind speed in September: 4.9mph

The windiest month (with the highest average wind speed) is January (6.2mph).
The calmest months (with the lowest average wind speed) are July and August (4.7mph).

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Average humidity in September
Bozeman, MT

Average humidity in September - Bozeman, MT
  • Average humidity in September: 56%

The month with the highest relative humidity is February (90%).
The month with the lowest relative humidity is August (51%).

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Average rainfall in September
Bozeman, MT

Average rainfall in September - Bozeman, MT
  • Average rainfall in September: 1.81"

The wettest month (with the highest rainfall) is May (2.83").
The driest month (with the least rainfall) is August (1.3").

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Average rainfall days in September
Bozeman, MT

Average rainfall days in September - Bozeman, MT
  • Average rainfall days in September: 11.2 days

The month with the highest number of rainy days is May (18.5 days).
The month with the least rainy days is January (4.4 days).

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Average snowfall in September
Bozeman, MT

Average snowfall in September - Bozeman, MT
  • Average snowfall in September: 2.05"

The month with the highest snowfall is February (15.51").
The months with the least snowfall are July and August (0").

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Average snowfall days in September
Bozeman, MT

Average snowfall days in September - Bozeman, MT
  • Average snowfall days in September: 1.5 days

The month with the highest number of snowfall days is February (20.3 days).
The month with the least snowfall days is July (0 days).

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Average daylight in September /
Average sunshine in September
Bozeman, MT

Average daylight in September / Average sunshine in September - Bozeman, MT
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).

  • Average sunshine in September: 9h and 4min

The month with the most sunshine is July (Average sunshine: 11h and 30min).
The months with the least sunshine are January and February (Average sunshine: 4h and 30min).

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Average sunshine days in September
Bozeman, MT

Average sunshine days in September - Bozeman, MT
  • Average sunshine days in September: 16.3 days

The month with the most sunshine days is September (16.3 days).
The month with the least sunshine days is April (7 days).

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Average UV index in September
Bozeman, MT

Average UV index in September - Bozeman, MT
  • Average UV index in September: 3

The month with the highest UV index is July (UV index 5).
The months with the lowest UV index are January, February, March, November and December (UV index 1).

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Average cloud cover in September
Bozeman, MT

Average cloud cover in September - Bozeman, MT
  • Average cloud cover in September: 24

The month with the most cloud cover is February (Cloud cover 61).
The month with the least cloud cover is August (Cloud cover 17).

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Average visibility in September
Bozeman, MT

Average visibility in September - Bozeman, MT
  • Average visibility in September: 6mi

The months with the highest visibility are June, July, August, September and October (6mi).
The months with the lowest visibility are January, February, March and December (4mi).

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Bozeman, Montana, USA

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