September weather forecast
Big Timber, MT

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Weather in September

September brings the first signs of autumn in Big Timber with temperatures easing off, daylight hours reducing, and a slight increase in rainfall. Chilly early mornings and late evenings contrast with milder afternoons, dressing the city in a spectrum of fall colors. The only snowfall in the last quarter- 0.51" (13mm), marks the onset of winter. Farmers markets thrive with fall harvests, while hikers are treated to the vibrant hues of fall foliage. Picturesque autumn landscapes, cool weather, and clear blue skies bring about a magical aura that attracts visitors from far and wide.

Temperature

The onset of September coincides with a reduction in the average high-temperature, falling from a moderately hot 76.6°F (24.8°C) in August to a refreshing 66.7°F (19.3°C). During September, the nighttime temperature averages of 45.3°F (7.4°C).

Humidity

In Big Timber, the average relative humidity in September is 51%.

Rainfall

In Big Timber, in September, during 9.8 rainfall days, 1.1" (28mm) of precipitation is typically accumulated. Throughout the year, there are 129.6 rainfall days, and 15.83" (402mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through May, September through December. September is the first month it typically snows in Big Timber, Montana. Throughout September, in the average 1 snowfall days, it receives 0.51" (13mm) of snow. Throughout the year, there are 67.6 snowfall days, and 38.19" (970mm) of snow is accumulated.

Daylight

In Big Timber, the average length of the day in September is 12h and 31min.
On the first day of September, sunrise is at 6:41 am and sunset at 7:57 pm. On the last day of the month, sunrise is at 7:17 am and sunset at 7:01 pm MDT.

Sunshine

In September, the average sunshine is 10.2h.

UV index

In September, the average daily maximum UV index is 3. A UV Index estimate of 3 to 5 represents a medium vulnerability from unsafe exposure to UV radiation for the average person.
Note: In September, the maximum UV index of 3 suggests this advice:
Ensure safety - Recommendations to avert sunburn are presented. Considering the strength of solar radiation at midday, one should avoid direct Sun exposure. Safeguard your eyes, ears, and face from sun rays with the aid of a wide-brim hat. Be on the lookout! Nearly twofold UV radiation from the Sun can be reflected by snow.
Updated: Jul 11, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are September temperatures in Big Timber?

In September, the average high-temperature and low-temperature in Big Timber are 66.7°F (19.3°C) and 45.3°F (7.4°C) respectively.

What is the average humidity in September?

In Big Timber, the average relative humidity in September is 51%.

How much does it rain in September?

In Big Timber, in September, it is raining for 9.8 days, with typically 1.1" (28mm) of accumulated precipitation.

When does it start snowing?

September is the first month it typically snows. Throughout September, in the average 1 snowfall days, it receives 0.51" (13mm) of snow.

What is the average length of the day in September?

In Big Timber, the average day length in September is 12h and 31min.

When are sunrise and sunset in September?

In September, on the first day of the month, sunrise is at 6:41 am and sunset at 7:57 pm. On the last day of the month, sunrise is at 7:17 am and sunset at 7:01 pm MDT.

How many hours of sunshine does Big Timber have in September?

The average sunshine duration in September is 10.2h.

What is the UV index reading in September?

In September, the average daily maximum UV index is 3. A UV Index value of 3 to 5 symbolizes a moderate vulnerability from exposure to the Sun's UV radiation.
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
Big Timber, MT

Average temperature in September - Big Timber, MT
  • Average high temperature in September: 66.7°F

The warmest month (with the highest average high temperature) is July (78.6°F).
The month with the lowest average high temperature is December (28.4°F).

  • Average low temperature in September: 45.3°F

The month with the highest average low temperature is August (52.9°F).
The coldest month (with the lowest average low temperature) is February (15.3°F).

Average pressure in September
Big Timber, MT

Average pressure in September - Big Timber, MT
  • Average pressure in September: 29.96"Hg

The months with the highest atmospheric pressure are January and December (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).

Average wind speed in September
Big Timber, MT

Average wind speed in September - Big Timber, MT
  • Average wind speed in September: 6.9mph

The windiest month (with the highest average wind speed) is January (11.1mph).
The calmest month (with the lowest average wind speed) is July (5.9mph).

Average humidity in September
Big Timber, MT

Average humidity in September - Big Timber, MT
  • Average humidity in September: 51%

The month with the highest relative humidity is February (80%).
The month with the lowest relative humidity is August (47%).

Average rainfall in September
Big Timber, MT

Average rainfall in September - Big Timber, MT
  • Average rainfall in September: 1.1"

The wettest month (with the highest rainfall) is May (3.15").
The driest month (with the least rainfall) is January (0.47").

Average rainfall days in September
Big Timber, MT

Average rainfall days in September - Big Timber, MT
  • Average rainfall days in September: 9.8 days

The month with the highest number of rainy days is May (19.8 days).
The months with the least rainy days are January and December (5.3 days).

Average snowfall in September
Big Timber, MT

Average snowfall in September - Big Timber, MT
  • Average snowfall in September: 0.51"

The month with the highest snowfall is March (7.09").
The months with the least snowfall are June, July and August (0").

Average snowfall days in September
Big Timber, MT

Average snowfall days in September - Big Timber, MT
  • Average snowfall days in September: 1 days

The month with the highest number of snowfall days is February (12.9 days).
The months with the least snowfall days are June, July and August (0 days).

Average daylight in September /
Average sunshine in September
Big Timber, MT

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

The month with the longest days is June (Average daylight: 15h and 42min).
The month with the shortest days is December (Average daylight: 8h and 42min).

  • Average sunshine in September: 10h and 1min

The month with the most sunshine is July (Average sunshine: 11h and 48min).
The months with the least sunshine are January, February and December (Average sunshine: 6h and 12min).

Average sunshine days in September
Big Timber, MT

Average sunshine days in September - Big Timber, MT
  • Average sunshine days in September: 17.8 days

The month with the most sunshine days is January (19.8 days).
The month with the least sunshine days is May (7.7 days).

Average UV index in September
Big Timber, MT

Average UV index in September - Big Timber, MT
  • Average UV index in September: 3

The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, April, October, November and December (UV index 2).

Average cloud cover in September
Big Timber, MT

Average cloud cover in September - Big Timber, MT
  • Average cloud cover in September: 21

The month with the most cloud cover is February (Cloud cover 41).
The months with the least cloud cover are July and August (Cloud cover 16).

Average visibility in September
Big Timber, MT

Average visibility in September - Big Timber, MT
  • Average visibility in September: 6mi

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

Big Timber, Montana, USA

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