September weather forecast
Shelby, MT

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Weather in September

A noticeable transition from summer to autumn occurs in September in Shelby, Montana. The high temperatures drop significantly to an average of 68.9°F (20.5°C) and the lush summer greenery begins to give way to vibrant autumn hues. Despite the occasional rainfall, the daylight hours remain considerably long, offering ample opportunities for morning walks and evening strolls. The city's landscape becomes a canvas of oranges, reds, and yellows, attracting leaf-peepers near and far. Festivals celebrating the fall harvest are common at this time, providing plenty of entertainment options.

Temperature

Transition into September marks a drop in the average high-temperature, moving from a moderately hot 79.9°F (26.6°C) in August to an agreeable 68.9°F (20.5°C). During the month of September, Shelby's nighttime temperature lowers to an average of 50.7°F (10.4°C).

Humidity

In Shelby, the average relative humidity in September is 46%.

Rainfall

In Shelby, Montana, in September, during 6.5 rainfall days, 0.59" (15mm) of precipitation is typically accumulated. Throughout the year, there are 84.2 rainfall days, and 9.29" (236mm) of precipitation is accumulated.

Snowfall

Months with snowfall in Shelby are January through May, September through December. September is the first month it typically snows. Throughout September, in the average 0.9 snowfall days, it receives 0.63" (16mm) of snow. In Shelby, during the entire year, snow falls for 53.7 days and aggregates up to 20.47" (520mm) of snow.

Daylight

The average length of the day in September in Shelby is 12h and 34min.
On the first day of the month, sunrise is at 6:45 am and sunset at 8:08 pm. On the last day of September, in Shelby, sunrise is at 7:26 am and sunset at 7:07 pm MDT.

Sunshine

In Shelby, the average sunshine in September is 9.7h.

UV index

In September, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a medium health hazard from unprotected exposure to Sun's UV rays for the ordinary person.
Note: The average daily UV index of 4 in September transforms into the following instructions:
Preventative actions are necessary - Recommendations to ward off sunburn are given. Midday Sun has the strongest UV rays, making it crucial to limit exposure and find shade. Equip yourself with UVA and UVB-filtering sunglasses on clear, sunny days. Take careful note! The UV radiation of the Sun can be nearly doubled by snow reflection.
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Frequently asked questions

What are September temperatures in Shelby?

The high-temperature, in September, in Shelby, is 68.9°F (20.5°C), while the low-temperature averages to 50.7°F (10.4°C). In July, the average heat index (a.k.a. 'feels like', 'apparent temperature'), which combines air temperature and relative humidity, is appraised at 80.6°F (27°C).

What is the average humidity in September in Shelby?

The average relative humidity in September in Shelby, Montana, is 46%.

How much does it rain in Shelby in September?

In Shelby, during September, the rain falls for 6.5 days and regularly aggregates up to 0.59" (15mm) of precipitation.

When does it start snowing in Shelby?

September is the first month it typically snows in Shelby. Throughout September, in the average 0.9 snowfall days, it receives 0.63" (16mm) of snow.

How many hours of daylight does Shelby have in September?

In Shelby, Montana, the average day length in September is 12h and 34min.

When are sunrise and sunset in September in Shelby?

On the first day of September in Shelby, sunrise is at 6:45 am and sunset at 8:08 pm. On the last day of the month, sunrise is at 7:26 am and sunset at 7:07 pm MDT.

How many hours of sunshine does Shelby have in September?

In Shelby, the average sunshine duration in September is 9.7h.

What is the UV index reading in September in Shelby?

In September, the average daily maximum UV index in Shelby is 4. A UV Index estimate of 3 to 5 represents a moderate health threat 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
Shelby, MT

Average temperature in September - Shelby, MT
  • Average high temperature in September: 68.9°F

The warmest month (with the highest average high temperature) is July (80.8°F).
The month with the lowest average high temperature is December (27.7°F).

  • Average low temperature in September: 50.7°F

The month with the highest average low temperature is August (58.3°F).
The coldest month (with the lowest average low temperature) is December (15.4°F).

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Average pressure in September
Shelby, MT

Average pressure in September - Shelby, MT
  • Average pressure in September: 29.94"Hg

The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.86"Hg).

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Average wind speed in September
Shelby, MT

Average wind speed in September - Shelby, MT
  • Average wind speed in September: 9.4mph

The windiest month (with the highest average wind speed) is April (11mph).
The calmest month (with the lowest average wind speed) is August (8.7mph).

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Average humidity in September
Shelby, MT

Average humidity in September - Shelby, MT
  • Average humidity in September: 46%

The month with the highest relative humidity is January (80%).
The month with the lowest relative humidity is August (40%).

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Average rainfall in September
Shelby, MT

Average rainfall in September - Shelby, MT
  • Average rainfall in September: 0.59"

The wettest month (with the highest rainfall) is June (2.01").
The driest months (with the least rainfall) are January and December (0.39").

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Average rainfall days in September
Shelby, MT

Average rainfall days in September - Shelby, MT
  • Average rainfall days in September: 6.5 days

The month with the highest number of rainy days is May (13.9 days).
The month with the least rainy days is February (3.1 days).

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Average snowfall in September
Shelby, MT

Average snowfall in September - Shelby, MT
  • Average snowfall in September: 0.63"

The month with the highest snowfall is February (4.17").
The months with the least snowfall are June, July and August (0").

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Average snowfall days in September
Shelby, MT

Average snowfall days in September - Shelby, MT
  • Average snowfall days in September: 0.9 days

The month with the highest number of snowfall days is February (10.3 days).
The months with the least snowfall days are July and August (0 days).

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

Average daylight in September / Average sunshine in September - Shelby, MT
  • Average daylight in September: 12h and 4min

The month with the longest days is June (Average daylight: 16h and 6min).
The month with the shortest days is December (Average daylight: 8h and 24min).

  • Average sunshine in September: 9h and 4min

The month with the most sunshine is July (Average sunshine: 11h and 54min).
The month with the least sunshine is January (Average sunshine: 5h and 24min).

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Average sunshine days in September
Shelby, MT

Average sunshine days in September - Shelby, MT
  • Average sunshine days in September: 22.2 days

The month with the most sunshine days is September (22.2 days).
The month with the least sunshine days is April (14.7 days).

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Average UV index in September
Shelby, MT

Average UV index in September - Shelby, MT
  • Average UV index in September: 4

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

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Average cloud cover in September
Shelby, MT

Average cloud cover in September - Shelby, MT
  • Average cloud cover in September: 23

The month with the most cloud cover is February (Cloud cover 46).
The month with the least cloud cover is July (Cloud cover 15).

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Average visibility in September
Shelby, MT

Average visibility in September - Shelby, 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).

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Shelby, Montana, USA

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