September weather forecast
Van Norman, MT

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Weather in September

The first month of the autumn, September, is still a pleasant month in Van Norman, Montana, with an average temperature ranging between min 54.9°F (12.7°C) and max 71.2°F (21.8°C).

Temperature

September comes with a decrease in the average high-temperature, falling from a moderately hot 82.6°F (28.1°C) in August to an agreeable 71.2°F (21.8°C). An average low-temperature of 54.9°F (12.7°C) is recorded in the month of September.

Humidity

In September, the average relative humidity is 44%.

Rainfall

In September, the rain falls for 8.7 days. Throughout September, 1.1" (28mm) of precipitation is accumulated. Throughout the year, there are 104.8 rainfall days, and 13.03" (331mm) of precipitation is accumulated.

Snowfall

January through May, September through December are months with snowfall. September is the first month it typically snows. Throughout September, in the average 0.1 snowfall days, it receives 0.04" (1mm) of snow. Throughout the year, there are 58.4 snowfall days, and 21.1" (536mm) of snow is accumulated.

Daylight

The average length of the day in September is 12h and 32min.
On the first day of September in Van Norman, sunrise is at 6:25 am and sunset at 7:44 pm. On the last day of the month, sunrise is at 7:04 am and sunset at 6:46 pm MDT.

Sunshine

In Van Norman, the average sunshine in September is 10.1h.

UV index

In September, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a medium health hazard from unsafe exposure to UV radiation for the ordinary person.
Note: The UV index of 4 during September leads to these advisories:
Be vigilant - A duty to shield skin and eyes from injury exists. The mid-day Sun emits the most powerful UV radiation, so seek shade and minimize exposure. Loose clothes with a tight weave are optimal for safeguarding yourself against the Sun's rays. Notice! The UV radiation of the Sun can be intensified nearly twofold due to the reflective quality of snow.
Updated: Aug 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the temperature in September?

The average high-temperature and low-temperature during September are 71.2°F (21.8°C) and 54.9°F (12.7°C) respectively. In August, the average heat index (a.k.a. 'felt air temperature', 'feels like'), which combines air temperature and relative humidity, is evaluated at 82.4°F (28°C).

What is the average humidity in September?

The average relative humidity in September is 44%.

How much does it rain in September?

In Van Norman, during September, the rain falls for 8.7 days and regularly aggregates up to 1.1" (28mm) of precipitation.

When does it start snowing?

September is the first month it typically snows. Throughout September, in the average 0.1 snowfall days, it receives 0.04" (1mm) of snow.

How many hours of daylight does Van Norman have in September?

In September, the average day length is 12h and 32min.

When are sunrise and sunset in September?

In September, on the first day of the month, sunrise is at 6:25 am and sunset at 7:44 pm. On the last day of the month, in Van Norman, sunrise is at 7:04 am and sunset at 6:46 pm MDT.

How many hours of sunshine does Van Norman have in September?

The average sunshine duration in September is 10.1h.

What is the UV index reading in September?

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

Average temperature in September - Van Norman, MT
  • Average high temperature in September: 71.2°F

The warmest month (with the highest average high temperature) is July (83.8°F).
The month with the lowest average high temperature is January (27.7°F).

  • Average low temperature in September: 54.9°F

The month with the highest average low temperature is July (64.4°F).
The coldest month (with the lowest average low temperature) is January (14.7°F).

Average pressure in September
Van Norman, MT

Average pressure in September - Van Norman, MT
  • Average pressure in September: 29.92"Hg

The months with the highest atmospheric pressure are January and February (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.83"Hg).

Average wind speed in September
Van Norman, MT

Average wind speed in September - Van Norman, MT
  • Average wind speed in September: 10.5mph

The windiest month (with the highest average wind speed) is April (12mph).
The calmest month (with the lowest average wind speed) is February (9.9mph).

Average humidity in September
Van Norman, MT

Average humidity in September - Van Norman, MT
  • Average humidity in September: 44%

The month with the highest relative humidity is January (82%).
The month with the lowest relative humidity is August (40%).

Average rainfall in September
Van Norman, MT

Average rainfall in September - Van Norman, MT
  • Average rainfall in September: 1.1"

The wettest months (with the highest rainfall) are May and June (1.89").
The driest month (with the least rainfall) is November (0.63").

Average rainfall days in September
Van Norman, MT

Average rainfall days in September - Van Norman, MT
  • Average rainfall days in September: 8.7 days

The month with the highest number of rainy days is May (14.5 days).
The month with the least rainy days is February (3.7 days).

Average snowfall in September
Van Norman, MT

Average snowfall in September - Van Norman, MT
  • Average snowfall in September: 0.04"

The month with the highest snowfall is December (4.45").
The months with the least snowfall are June, July and August (0").

Average snowfall days in September
Van Norman, MT

Average snowfall days in September - Van Norman, MT
  • Average snowfall days in September: 0.1 days

The month with the highest number of snowfall days is December (12.5 days).
The months with the least snowfall days are July and August (0 days).

Average daylight in September /
Average sunshine in September
Van Norman, MT

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

The month with the longest days is June (Average daylight: 15h and 54min).
The month with the shortest days is December (Average daylight: 8h and 30min).

  • Average sunshine in September: 10h and 1min

The month with the most sunshine is July (Average sunshine: 11h and 54min).
The months with the least sunshine are January and February (Average sunshine: 4h and 54min).

Average sunshine days in September
Van Norman, MT

Average sunshine days in September - Van Norman, MT
  • Average sunshine days in September: 18.7 days

The month with the most sunshine days is November (19.1 days).
The month with the least sunshine days is April (12.3 days).

Average UV index in September
Van Norman, MT

Average UV index in September - Van Norman, MT
  • Average UV index in September: 4

The month with the highest UV index is July (UV index 7).
The month with the lowest UV index is December (UV index 1).

Average cloud cover in September
Van Norman, MT

Average cloud cover in September - Van Norman, MT
  • Average cloud cover in September: 23

The month with the most cloud cover is February (Cloud cover 49).
The months with the least cloud cover are July and August (Cloud cover 16).

Average visibility in September
Van Norman, MT

Average visibility in September - Van Norman, MT
  • Average visibility in September: 6mi

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

Van Norman, Montana, USA

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