September weather forecast
Sweet Grass, MT

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Weather in September

September, the first month of the autumn in Sweet Grass, is still a refreshing month, with an average temperature ranging between min 48.4°F (9.1°C) and max 67.6°F (19.8°C).

Temperature

Sweet Grass's September weather comes with a decrease in average high-temperatures, moving from a warm 78.1°F (25.6°C) in August to a comfortable 67.6°F (19.8°C). During September, Sweet Grass's temperature falls to a steady low-temperature average of 48.4°F (9.1°C).

Humidity

In Sweet Grass, the average relative humidity in September is 49%.

Rainfall

In Sweet Grass, in September, during 6.2 rainfall days, 0.71" (18mm) of precipitation is typically accumulated. In Sweet Grass, during the entire year, the rain falls for 70.4 days and collects up to 8.46" (215mm) of precipitation.

Snowfall

January through May, September through December are months with snowfall. September is the first month it typically snows in Sweet Grass. Throughout September, in the average 0.8 snowfall days, it receives 0.51" (13mm) of snow. Throughout the year, there are 54.3 snowfall days, and 19.49" (495mm) of snow is accumulated.

Daylight

In Sweet Grass, Montana, the average length of the day in September is 12h and 34min.
On the first day of September in Sweet Grass, sunrise is at 6:45 am and sunset at 8:09 pm. On the last day of the month, sunrise is at 7:27 am and sunset at 7:07 pm MDT.

Sunshine

In Sweet Grass, the average sunshine in September is 9.6h.

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 ordinary individuals.
Note: The maximum daily UV index of 4 during September translates into the following directions:
Heed the precautions - Suggestions to avoid sunburn are made. Sun exposure should be minimized, especially during midday, to avoid harmful UV radiation. For effective sun eye protection, rely on sunglasses certified for UVA and UVB resistance. Notice this! Nearly double the intensity of the Sun's UV radiation can be caused by snow reflection.
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Frequently asked questions

What are September temperatures in Sweet Grass?

In Sweet Grass, in September, the average high-temperature is 67.6°F (19.8°C), and the average low-temperature is 48.4°F (9.1°C).

What is the average humidity in September in Sweet Grass?

The average relative humidity in September in Sweet Grass, Montana, is 49%.

How many days does it rain in September in Sweet Grass?

In Sweet Grass, in September, it is raining for 6.2 days, with typically 0.71" (18mm) of accumulated precipitation.

When does it start to snow in Sweet Grass?

September is the first month it typically snows in Sweet Grass, Montana. Throughout September, in the average 0.8 snowfall days, it receives 0.51" (13mm) of snow.

How many hours of daylight does Sweet Grass have in September?

In September, the average day length in Sweet Grass is 12h and 34min.

What time are sunrise and sunset in September in Sweet Grass?

On the first day of September in Sweet Grass, sunrise is at 6:45 am and sunset at 8:09 pm. On the last day of the month, sunrise is at 7:27 am and sunset at 7:07 pm MDT.

How long on average sun shines in September in Sweet Grass?

In Sweet Grass, the average sunshine duration in September is 9.6h.

What is the UV index intensity in September in Sweet Grass?

The average daily maximum UV index in September in Sweet Grass, Montana, is 4. A UV Index value of 3 to 5 symbolizes a medium health risk 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
Sweet Grass, MT

Average temperature in September - Sweet Grass, MT
  • Average high temperature in September: 67.6°F

The warmest month (with the highest average high temperature) is July (78.8°F).
The month with the lowest average high temperature is December (27.1°F).

  • Average low temperature in September: 48.4°F

The month with the highest average low temperature is August (55.2°F).
The coldest month (with the lowest average low temperature) is December (15.3°F).

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Average pressure in September
Sweet Grass, MT

Average pressure in September - Sweet Grass, MT
  • Average pressure in September: 29.95"Hg

The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.87"Hg).

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Average wind speed in September
Sweet Grass, MT

Average wind speed in September - Sweet Grass, MT
  • Average wind speed in September: 9.5mph

The windiest month (with the highest average wind speed) is January (11.8mph).
The calmest months (with the lowest average wind speed) are July and August (8.8mph).

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Average humidity in September
Sweet Grass, MT

Average humidity in September - Sweet Grass, MT
  • Average humidity in September: 49%

The month with the highest relative humidity is January (79%).
The month with the lowest relative humidity is August (43%).

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Average rainfall in September
Sweet Grass, MT

Average rainfall in September - Sweet Grass, MT
  • Average rainfall in September: 0.71"

The wettest month (with the highest rainfall) is June (1.77").
The driest month (with the least rainfall) is July (0.31").

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Average rainfall days in September
Sweet Grass, MT

Average rainfall days in September - Sweet Grass, MT
  • Average rainfall days in September: 6.2 days

The month with the highest number of rainy days is May (10.4 days).
The month with the least rainy days is November (2.6 days).

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Average snowfall in September
Sweet Grass, MT

Average snowfall in September - Sweet Grass, MT
  • Average snowfall in September: 0.51"

The month with the highest snowfall is February (3.58").
The months with the least snowfall are June, July and August (0").

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Average snowfall days in September
Sweet Grass, MT

Average snowfall days in September - Sweet Grass, MT
  • Average snowfall days in September: 0.8 days

The month with the highest number of snowfall days is December (10.2 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
Sweet Grass, MT

Average daylight in September / Average sunshine in September - Sweet Grass, 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 18min).

  • Average sunshine in September: 9h and 4min

The month with the most sunshine is July (Average sunshine: 12h and 0min).
The months with the least sunshine are January and December (Average sunshine: 5h and 36min).

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Average sunshine days in September
Sweet Grass, MT

Average sunshine days in September - Sweet Grass, MT
  • Average sunshine days in September: 22.4 days

The month with the most sunshine days is July (23.5 days).
The month with the least sunshine days is April (17.4 days).

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Average UV index in September
Sweet Grass, MT

Average UV index in September - Sweet Grass, 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
Sweet Grass, MT

Average cloud cover in September - Sweet Grass, MT
  • Average cloud cover in September: 23

The month with the most cloud cover is February (Cloud cover 43).
The month with the least cloud cover is July (Cloud cover 15).

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Average visibility in September
Sweet Grass, MT

Average visibility in September - Sweet Grass, 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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Sweet Grass, Montana, USA

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