September weather forecast
White Sulphur Springs, MT

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Weather in September

September signals the onset of fall in White Sulphur Springs. As the temperatures cool down to an average high of 67.1°F (19.5°C), leaves begin changing colors. Also, rainfall slightly increases to 1.1" (28mm), a signal that autumn is knocking at the door. Traditionally a harvest season, the landscape turns into an array of harvest hues and is a spectacle that shouldn't be missed. Mountain wildlife is also active, preparing for the winter.

Temperature

Start of September in White Sulphur Springs brings a shift in the average high-temperature, falling from August's warm 77.5°F (25.3°C) to an enjoyable 67.1°F (19.5°C). White Sulphur Springs, in September, displays a significant temperature downturn during the night, with an average reading of 42.4°F (5.8°C).

Humidity

In White Sulphur Springs, the average relative humidity in September is 54%.

Rainfall

In White Sulphur Springs, in September, during 8.7 rainfall days, 1.1" (28mm) of precipitation is typically accumulated. Throughout the year, there are 103.1 rainfall days, and 13.31" (338mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through June, September through December. September is the first month it typically snows. Throughout September, in the average 1.4 snowfall days, it receives 1.85" (47mm) of snow. Throughout the year, there are 97.8 snowfall days, and 52.68" (1338mm) of snow is accumulated.

Daylight

The average length of the day in September is 12h and 32min.
On the first day of September, sunrise is at 6:44 am and sunset at 8:01 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 7:04 pm MDT.

Sunshine

The average sunshine in September is 10.2h.

UV index

The average daily maximum UV index in September is 3. A UV Index estimate of 3 to 5 represents a moderate threat to health from unprotected exposure to Sun's UV rays for average individuals.
Note: In September, the UV index of 3 transforms into the following advice:
Proceed with care. Light skin individuals may be exposed to burns in fewer than 30 minutes. Direct exposure to the Sun during its peak hours around mid-day should be minimized for safety. Enhance your sun protection with tightly woven, yet airy clothing. Remember! The Sun's UV radiation can be magnified almost twofold by the reflection of snow.
Updated: Jun 22, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are the temperatures in September?

The high-temperature, in September, in White Sulphur Springs, records 67.1°F (19.5°C), while the low-temperature is 42.4°F (5.8°C).

What is the average humidity in September?

In White Sulphur Springs, the average relative humidity in September is 54%.

How many days does it rain in September?

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

When does it start to snow?

September is the first month it typically snows. Throughout September, in the average 1.4 snowfall days, it receives 1.85" (47mm) of snow.

What is the average length of the day in September?

In White Sulphur Springs, the average day length in September is 12h and 32min.

When are sunrise and sunset in September?

In September, on the first day of the month, sunrise is at 6:44 am and sunset at 8:01 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 7:04 pm MDT.

How many hours of sunshine does White Sulphur Springs have in September?

In White Sulphur Springs, the average sunshine duration in September is 10.2h.

What is the UV index reading in September?

In White Sulphur Springs, the average daily maximum UV index in September is 3. A UV Index of 3 to 5 symbolizes a moderate vulnerability 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
White Sulphur Springs, MT

Average temperature in September - White Sulphur Springs, MT
  • Average high temperature in September: 67.1°F

The warmest month (with the highest average high temperature) is July (79.5°F).
The month with the lowest average high temperature is December (25.3°F).

  • Average low temperature in September: 42.4°F

The month with the highest average low temperature is July (48.7°F).
The coldest month (with the lowest average low temperature) is December (10.9°F).

Average pressure in September
White Sulphur Springs, MT

Average pressure in September - White Sulphur Springs, MT
  • Average pressure in September: 29.97"Hg

The month with the highest atmospheric pressure is January (30.18"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).

Average wind speed in September
White Sulphur Springs, MT

Average wind speed in September - White Sulphur Springs, MT
  • Average wind speed in September: 5mph

The windiest month (with the highest average wind speed) is April (5.9mph).
The calmest month (with the lowest average wind speed) is August (4.7mph).

Average humidity in September
White Sulphur Springs, MT

Average humidity in September - White Sulphur Springs, MT
  • Average humidity in September: 54%

The month with the highest relative humidity is January (88%).
The month with the lowest relative humidity is August (48%).

Average rainfall in September
White Sulphur Springs, MT

Average rainfall in September - White Sulphur Springs, MT
  • Average rainfall in September: 1.1"

The wettest month (with the highest rainfall) is May (2.05").
The driest month (with the least rainfall) is January (0.59").

Average rainfall days in September
White Sulphur Springs, MT

Average rainfall days in September - White Sulphur Springs, MT
  • Average rainfall days in September: 8.7 days

The month with the highest number of rainy days is May (15.1 days).
The month with the least rainy days is November (3.8 days).

Average snowfall in September
White Sulphur Springs, MT

Average snowfall in September - White Sulphur Springs, MT
  • Average snowfall in September: 1.85"

The month with the highest snowfall is February (9.61").
The months with the least snowfall are July and August (0").

Average snowfall days in September
White Sulphur Springs, MT

Average snowfall days in September - White Sulphur Springs, MT
  • Average snowfall days in September: 1.4 days

The month with the highest number of snowfall days is February (16.5 days).
The months with the least snowfall days are July and August (0 days).

Average daylight in September /
Average sunshine in September
White Sulphur Springs, MT

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

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

  • Average sunshine in September: 10h and 1min

The month with the most sunshine is July (Average sunshine: 11h and 48min).
The month with the least sunshine is January (Average sunshine: 5h and 36min).

Average sunshine days in September
White Sulphur Springs, MT

Average sunshine days in September - White Sulphur Springs, MT
  • Average sunshine days in September: 18.4 days

The month with the most sunshine days is September (18.4 days).
The month with the least sunshine days is April (10.6 days).

Average UV index in September
White Sulphur Springs, MT

Average UV index in September - White Sulphur Springs, 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 and December (UV index 1).

Average cloud cover in September
White Sulphur Springs, MT

Average cloud cover in September - White Sulphur Springs, MT
  • Average cloud cover in September: 20

The month with the most cloud cover is February (Cloud cover 49).
The month with the least cloud cover is August (Cloud cover 14).

Average visibility in September
White Sulphur Springs, MT

Average visibility in September - White Sulphur Springs, MT
  • Average visibility in September: 6mi

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

White Sulphur Springs, Montana, USA

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