September weather forecast
Columbia Falls, MT

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Weather in September

September weather in Columbia Falls, Montana, experiences a noticeable shift from hot summer temperatures to a cooler fall-like weather. There's an appreciable cool-down from the high August temperature of 76.8°F (24.9°C), signaling the onset of Autumn. The shorter days and an increase in rainfall contribute to the changing atmosphere of Columbia Falls. As October approaches, expect a further drop in temperature and daylight hours along with an increase in cloud cover. Even so, September's pleasant weather conditions make it an appealing time for individuals who prefer a balance between summer warmth and autumn cool.

Temperature

Columbia Falls's transition into September involves a shift in temperature, receding from a warm 76.8°F (24.9°C) in August to an enjoyable 65.5°F (18.6°C). Columbia Falls experiences a significant contrast between daily highs and an average nighttime temperature of 39.2°F (4°C) during September.

Humidity

The average relative humidity in September is 64%.

Rainfall

In Columbia Falls, in September, during 8.5 rainfall days, 0.71" (18mm) of precipitation is typically accumulated. In Columbia Falls, during the entire year, the rain falls for 126.4 days and collects up to 11.22" (285mm) of precipitation.

Snowfall

January through May, September through December are months with snowfall. September is the first month it typically snows. Throughout September, in the average 0.3 snowfall days, it receives 0.04" (1mm) of snow. In Columbia Falls, during the entire year, snow falls for 97 days and aggregates up to 33.86" (860mm) of snow.

Daylight

In Columbia Falls, the average length of the day in September is 12h and 34min.
On the first day of the month, sunrise is at 6:55 am and sunset at 8:17 pm. On the last day of September, sunrise is at 7:35 am and sunset at 7:17 pm MDT.

Sunshine

In Columbia Falls, the average sunshine in September is 9.4h.

UV index

The average daily maximum UV index in September in Columbia Falls is 3. A UV Index value of 3 to 5 symbolizes a moderate threat to health from unprotected exposure to Sun's UV rays for the average person.
Note: The maximum daily UV index, 3 in September, converts into the following recommendations:
Heed the precautions - Protecting the skin and eyes from damage is compulsory. Solar radiation is at its peak intensity during midday, so it's advisable to stay indoors or in the shade. For optimum UV protection, wear sun-resistant attire complemented with a hat and quality shades. Remember! The Sun's UV radiation can be magnified almost twofold by the reflection of snow.
Updated: Aug 21, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the usual temperature for Columbia Falls in September?

September temperatures vary between a high-temperature of 65.5°F (18.6°C) and a low-temperature of 39.2°F (4°C).

What is the average humidity in September?

In Columbia Falls, the average relative humidity in September is 64%.

How much does it rain in September?

In Columbia Falls, in September, it is raining for 8.5 days, with typically 0.71" (18mm) of accumulated precipitation.

When does it start to snow?

September is the first month it typically snows. Throughout September, in the average 0.3 snowfall days, it receives 0.04" (1mm) of snow.

How many hours of daylight does Columbia Falls have in September?

In Columbia Falls, the average day length in September is 12h and 34min.

When is the sunrise / sunset in September?

In September, on the first day of the month, sunrise is at 6:55 am and sunset at 8:17 pm. On the last day of the month, sunrise is at 7:35 am and sunset at 7:17 pm MDT.

How long on average sun shines in September?

In Columbia Falls, the average sunshine duration in September is 9.4h.

What is the UV index intensity in September?

In September, the average daily maximum UV index is 3. A UV Index estimate of 3 to 5 represents a medium hazard to health from unprotected exposure to 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
Columbia Falls, MT

Average temperature in September - Columbia Falls, MT
  • Average high temperature in September: 65.5°F

The warmest month (with the highest average high temperature) is July (77.9°F).
The month with the lowest average high temperature is December (25.7°F).

  • Average low temperature in September: 39.2°F

The month with the highest average low temperature is August (45.5°F).
The coldest month (with the lowest average low temperature) is February (13.5°F).

Average pressure in September
Columbia Falls, MT

Average pressure in September - Columbia Falls, MT
  • Average pressure in September: 29.97"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed in September
Columbia Falls, MT

Average wind speed in September - Columbia Falls, MT
  • Average wind speed in September: 3.8mph

The windiest month (with the highest average wind speed) is April (4.6mph).
The calmest months (with the lowest average wind speed) are August and December (3.7mph).

Average humidity in September
Columbia Falls, MT

Average humidity in September - Columbia Falls, MT
  • Average humidity in September: 64%

The month with the highest relative humidity is January (93%).
The month with the lowest relative humidity is August (55%).

Average rainfall in September
Columbia Falls, MT

Average rainfall in September - Columbia Falls, MT
  • Average rainfall in September: 0.71"

The wettest month (with the highest rainfall) is June (1.42").
The driest month (with the least rainfall) is August (0.43").

Average rainfall days in September
Columbia Falls, MT

Average rainfall days in September - Columbia Falls, MT
  • Average rainfall days in September: 8.5 days

The month with the highest number of rainy days is April (15.8 days).
The month with the least rainy days is August (6.3 days).

Average snowfall in September
Columbia Falls, MT

Average snowfall in September - Columbia Falls, MT
  • Average snowfall in September: 0.04"

The month with the highest snowfall is January (7.72").
The months with the least snowfall are June, July and August (0").

Average snowfall days in September
Columbia Falls, MT

Average snowfall days in September - Columbia Falls, MT
  • Average snowfall days in September: 0.3 days

The month with the highest number of snowfall days is December (19.1 days).
The months with the least snowfall days are July and August (0 days).

Average daylight in September /
Average sunshine in September
Columbia Falls, MT

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

The month with the longest days is June (Average daylight: 16h and 0min).
The month with the shortest days is December (Average daylight: 8h and 24min).

  • Average sunshine in September: 9h and 2min

The month with the most sunshine is July (Average sunshine: 11h and 54min).
The month with the least sunshine is January (Average sunshine: 3h and 30min).

Average sunshine days in September
Columbia Falls, MT

Average sunshine days in September - Columbia Falls, MT
  • Average sunshine days in September: 19 days

The month with the most sunshine days is July (21.5 days).
The month with the least sunshine days is March (7.7 days).

Average UV index in September
Columbia Falls, MT

Average UV index in September - Columbia Falls, 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, November and December (UV index 1).

Average cloud cover in September
Columbia Falls, MT

Average cloud cover in September - Columbia Falls, MT
  • Average cloud cover in September: 24

The month with the most cloud cover is January (Cloud cover 65).
The months with the least cloud cover are July and August (Cloud cover 15).

Average visibility in September
Columbia Falls, MT

Average visibility in September - Columbia Falls, MT
  • Average visibility in September: 6mi

The months with the highest visibility are May, June, July, August, September and October (6mi).
The month with the lowest visibility is January (3mi).

Columbia Falls, Montana, USA

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